Talk:Birth

From Embryology

Birth lecture

Introduction

Historic model of birth

There are a great number of comprehensive, scientific and general, books and articles that cover Parturition, Birth or Childbirth.

Birth or parturition is a critical stage in development, representing in mammals a transition from direct maternal support of fetal development, physical expulsion and establishment of the newborns own respiratory, circulatory and digestive systems.

Textbooks

  • Human Embryology (2nd ed.) Larson Chapter 15 p471-488
  • The Developing Human: Clinically Oriented Embryology (6th ed.) Moore and Persaud Chapter 7 p129-167

Gestation Period

Newborn

The median duration of gestation for first births from assumed ovulation to delivery was 274 days (just over 39 weeks). For multiple births, the median duration of pregnancy was 269 days (38.4 weeks).

"...one should count back 3 months from the first day of the last menses, then add 15 days for primiparas or 10 days for multiparas, instead of using the common algorithm for Naegele's rule." Reference: Mittendorf R, Williams MA, Berkey CS, Cotter PF. The length of uncomplicated human gestation. Obstet Gynecol. 1990 Jun;75(6):929-32

Historically, Franz Carl Naegele (1777-1851) developed the first scientific rule for estimating length of a pregnany.

Childbirth

Birth Stage 2
  • Parturition (Latin, parturitio = "childbirth") describes expelling the fetus, placenta and fetal membranes and is probably initiated by fetus not mother.
  • Preterm birth - Risks of preterm birth in abnormal low birth weight (intrauterine growth restriction) and high (large for gestational age) categories are 2- to 3-fold greater than the risk among appropriate-for-gestational-age infants.
  • Maternal labor - uterine contractions and dilation of cervix, process under endocrine regulation
  • Placenta and fetal membranes - (Latin, secundina = "following") expelled after neonate birth

Uterine Myometrial Changes

  • Smooth muscle fibers - hypertrophy not proliferation
  • Stretching of myometrium - stimulates spontaneous muscular contraction, during pregnancy progesterone inhibits contraction
  • Stimulating contraction - increased estrogen levels (placental secretion sensitizes smooth muscle), increased oxytocin levels (fetal oxytocin release- force and frequency of contraction), fetal pituitary prostaglandin production (estrogen and oxytocin stimulate endometrial production of prostaglandin)

Progesterone

  • maintains pregnancy - initially synthesized by corpus luteum, then levels maintained by placenta
  • hyperpolarizes myometrial cells (-65 mV), reduces excitability and conductivity
  • Level in plasma may fall just before parturition, definitely decreases following delivery of placenta

Estrogens

  • Group of steroidal hormones, peak when parturition begins
  • induce increased synthesis of actomyosin and ATP in myometrial cells
  • alter membrane potential (-50 Mv) enhances excitation/conduction
  • act to directly increase myometrial contraction
  • indirectly by increasing oxytocin from pituitary gland
  • Estriol - synthesized by fetus and placenta

Oxytocin

  • Peptide hormone (8aa) from maternal posterior pituitary, initiation and maintenance of labour (synthetic form labour induction)
  • myometrium sensitivity to oxytocin (increased by estrogen, decreased by progesterone)
  • stimulus for release - mechanical stimulation of uterus, cervix and vagina (ethanol inhibits release)

Prostaglandins

  • hydroxy fatty acids - sythesized by placenta, amniotic fliud contains mainly PGF2 alpha, causes myometrial contraction (also in maternal plasma)
  • PGF2 alpha and PGE2 - used to induce labour (intravenous, oral, intravaginal, intraamniotic)
  • Aspirin inhibitor of PG synthesis - leads to increased duration of pregnancy

External Environment

  • mainly shown in other species parturition occurs in peaceful undisturbed surroundings, stress may have an inhibitory effect on oxytocin release
  • Most human births occur at night (peak at 3am) diurnal rhythm influence

Labor Stages

Birth Stage 2

Stage 1 - dilatation

  • uterine contractions 10 minutes apart, function to dilate cervix fetal membranes rupture releasing amnion, 7 -12 hours (longer for first child)

Stage 2 - expulsion

  • uterine contractions push fetus through cervix and vagina, contractions 2-3 minutes apart, 20 - 50 minutes

Stage 3 - placental

  • following child delivery contractions continue to expel placenta. haematoma separates placenta from uterine wall, separation occurs at spongy layer of decidua basalis, 15 minutes

Stage 4 - recovery

  • continued myometrial contraction closes spiral arteries, 2+ hours

Newborn Homoeostasis

Brown adipose tissue

Newborn has to establish new functioning systems in a balanced and regulated manner (homoeostasis).

  • lung function
  • circulatory changes
  • thermoregulation
  • endocrine function
  • nutrition
  • gastrointestinal tract function
  • waste
  • kidney function

Glucocorticoids - have an important role in the preparation for birth, including involvement in lung and cardiac development, and the maturation of enzymes in a variety of pathways.

Respiration

Neonatal rib orientation
  • Lungs at birth collapsed and fluid-filled - replaced with air by powerful inspiratory movement and absorption through the alveoli
  • Lung epithelia has to rapidly change from its prenatal secretory function to that of fluid absorbtion.
    • initiated by a late fetal change in alveolar epithelial cell (AEC) chloride and fluid secretion to sodium and fluid absorption.
    • absorption requires sodium-potassium ATPase (Na-K-ATPase) together with apical sodium entry mechanisms (Epithelial Sodium Channels, ENaC)
    • Fetal thyroid hormone is thought to have a hormonal role in this developmental switch
  • These changes and pressure also lead to the pulmonary sytem becoming activated and changes in the circulatory shunting that existed before birth.
  • During the late fetal period regular fetal breathing movements (FBM) also occur preparing both the skeletomuscular sysyem and lungs mechanically for respiration.
  • Respiratory Rate is higher than adult (30 breaths/minute).
  • Rib Orientation - Infant rib is virtually horizontal, allowing diaphragmatic breathing only. Adult rib orientation is oblique (both anterior and lateral views), allows for pump-handle and bucket handle types of inspiration.

Postnatal Development - Respiratory

Cardiovascular

  • Umbilical Vasculature - The umbilical blood vessel cavity is lost postnatally over the course of weeks to months after birth. The adult anatomical remnant of the umbilical vein between the umbilicus and liver is the ligamentum teres.
  • Foramen Ovale - two separate forms of foramen ovale closure; functional and structural. Functional closure begins at the first breath and is rapid. Structural (anatomical) closure is much slower and generally occurs before the end of the first year.
  • Ductus Arteriosus - a direct connection between the pulmonary trunk and the dorsal aorta. Postnatal closure occurs initially by by smooth muscle contraction and begins at the first breath and is rapid, completed within the first day (about 15 hr after birth). Anatomical closure is much slower occuring by 2–3 weeks after birth (33% of infants), by 2 months (90% of infants) and by 1 year (99% of infants). The adult anatomical remnant of the ductus arteriosus is the ligamentum arteriosum.
  • Ductus Venosus - connects portal and umbilical blood to the inferior vena cava. Functional closure occurs postnatally within hours. Structural closure commences days after birth and completes by 18 to 20 days. The adult anatomical remnant of the ductus venosus is the ligamentum venosum (a dorsal fissure on the liver).

Neonatal Testing

APGAR

Apgar.jpg

Measured at one and five minutes after birth the Score values are totalled for all indicators: 7-10 is considered normal, 4-7 may require resuscitative measures, 3 and below require immediate resuscitation.

In recent years there has been some controversy of the relevance and accuracy of some of the criteria used in this test, though many feel it is still an invaluable initial assessment tool particularly where medical services are limited.

Indicator Score 0 Score 1 Score 2
Activity (muscle tone) Limp; no movement Some flexion of arms and legs Active motion
Pulse (heart rate) No heart rate Fewer than 100 beats per minute At least 100 beats per minute
Grimace (reflex response) No response to airways being suctioned Grimace during suctioning Grimace and pull away, cough, or sneeze during suctioning
Appearance (color) The baby's whole body is completely bluish-gray or pale Good color in body with bluish hands or feet Good color all over
Respiration (breathing) Not breathing Weak cry; may sound like whimpering, slow or irregular breathing Good, strong cry; normal rate and effort of breathing


Reference: Apgar, V. A proposal for a new method of evaluation of the newborn infant. Curr Res Anesth Analg. 1953 Jul-Aug;32(4):260-7. PMID:13083014

Guthrie Test

Robert Guthrie
Guthrie card
  • Blood is collected using a heelprick and spotted onto a test sheet to dry for later testing.
  • Different countries and medical services have different policies on not only what will be diagnostically tested, but also how long the test card will be kept following analysis.

Routine Screened Disorders

  • Biotinidase Deficiency (OMIM)
  • Congenital Adrenal Hyperplasia (CAH) (OMIM)
  • Congenital Hypothyroidism (CH)
  • Congenital Toxoplasmosis
  • Cystic Fibrosis (CF) (OMIM)
  • Galactosemia (GAL) (OMIM)
  • Homocystinuria (OMIM)
  • Maple Syrup Urine Disease (MSUD) (OMIM)
  • Medium-Chain Acyl-CoA Dehydrogenase Deficiency (MCAD) (OMIM)

Heart

  • An electrocardiogram (ECG / EKG) is an electrical recording of the heart which may identify electrical disorders including long QT syndrome.

Hip Displasia

  • Non-specific hip instability is a common finding in newborns, particularly in females.
  • More than 80% of clinically unstable hips at birth resolve spontaneously. Screening newborns for Developmental dysplasia of the hip (DDH) shows an incidence in infants between 1.5 and 20 per 1000 births. This incidence is influenced by several factors (diagnostic criteria, gender, genetic and racial factors, and age of the population).

Links: Musculoskeletal Abnormalities- Congenital Dislocation of the Hip | [hipdyssyn.pdf Screening for Developmental Dysplasia of the Hip PDF] | Screening for developmental dysplasia of the hip. Evidence synthesis no. 42. Rockville, Md.: Agency for Healthcare Research and Quality http://www.ahrq.gov/downloads/pub/prevent/pdfser/hipdyssyn.pdf | U.S. Preventive Service Task Force. Screening for developmental dysplasia of the hip: recommendation statement. Am Fam Physician. 2006 Jun 1;73(11):1992-6.

Hearing

  • The incidence of significant permanent hearing loss is approximately 1-3/1000 newborns.
  • Neonatal hearing screening is carried out in the USA, UK and in Australia (2002 NSW Statewide Infant Screening Hearing Program, SWISH) There is a general guide giving a timetable for a number of simple responses that a neonate should make if hearing has developed normally.
  • State Wide Infant Screening Hearing Program (SWISH) a newborn hearing testing program using an automated auditory response technology (AABR). Program was introduced in NSW Australia in 2002 across 17 area health service coordinators. It is thought that in NSW 86,000 births/year = 86-172 babies potentially born with significant permanent hearing loss.
  • Automated Auditory Brainstem Response (AABR) uses a stimulus which is delivered through earphones and detected by scalp electrodes. The test takes between 8 to 20 minutes and has a sensitivity 96-99%.

Premature Birth

Premature infant
Year < 34 weeks % 34-36 weeks % total preterm %
1990 3.3 7.3 10.6
1995 3.3 7.7 11
2000 3.4 8.2 11.6
2005 3.6 9.1 12.7

Data from: Prevention of preterm birth: a renewed national priority Damus K. Curr Opin Obstet Gynecol. 2008 Dec;20(6):590-6 PMID: 18989136

Australia Recommendations

Perinatal care at the borderlines of viability: a consensus statement based on a NSW and ACT consensus workshop (February 2005) published in The Medical Journal of Australia 2006; 185 (9): 495-500.

  • < 23 weeks survival is minimal and the risk of major morbidity is so high that initiation of resuscitation is not appropriate.
  • 23 weeks active treatment may be discussed, but would be discouraged in NSW/ACT neonatal intensive care units.
  • 23 to 25 weeks otherwise normal infant, there is an increasing obligation to treat. However, it is acceptable medical practice not to initiate intensive care if parents so wish, following appropriate counselling.
  • 24 weeks antenatal transfer to a tertiary centre for fetal reasons is indicated. The option of non-initiation of intensive care/resuscitation should be offered.
  • 25 weeks active treatment is usually offered, but the option of non-initiation of intensive care/resuscitation (presence of adverse fetal factors such as twin-to-twin transfusion, intrauterine growth restriction or chorioamnionitis) should also be discussed.
  • 26 weeks + otherwise normal infant the obligation to treat is very high, and treatment should generally be initiated unless there are exceptional circumstances.

Abnormalities

There are many birth associated abnormalities, only a few examples are listed below. (More? Abnormal Development)

Labor Abnormalities

  • Premature Labor - occurs 7 -10% in humans, contributes 75% perinatal mortalities
  • Underdeveloped Systems - particularly respiratory, surfactant, hyaline membrane disease (see respiratory development lecture)

Placental Abnormalities

  • placenta accreta - abnormal adherence, with absence of decidua basalis
  • placenta percreta - villi penetrate myometrium
  • placenta previa - placenta overlies internal os of uterus, abnormal bleeding, cesarian delivery

Breech Delivery

Breech Birth
Breech Birth
  • Historically, breech-born children were called agrippi, meaning "delivered with difficulty" (aegre parti).
  • Breech position - occurs in about 3% of fetuses when buttocks or lower limb are presented to the birth canal rather than normal cephalic (head-first) position (presentation).
  • Associated increased - perinatal mortality, perinatal morbidity, recurrence in successive siblings

Current research suggests that genetically that both men and women delivered in breech presentation at term could also contribute to an increased risk of breech delivery in their offspring. ([#18369204 Nordtveit TI, etal., 2008])

Meconium aspiration syndrome

  • meconium is formed from gut and associated organ secretions as well as cells and debris from the swallowed amniotic fluid.
  • Meconium accumulates during the fetal period in the large intestine (bowel). It can be described as being a generally dark colour (green black) , sticky and odourless.
  • Normally this meconium is defaecated (passed) postnatally over the first 48 hours and then transitional stools from day 4.
  • Abnormally this meconium is defaecated in utero, due to oxygen deprivation and other stresses. Premature discharge into the amniotic sac can lead to mixing with amniotic fluid and be reswallowed by the fetus. This is meconium aspiration syndrome and can damage both the developing lungs and placental vessels.

Necrotizing Enterocolitis

Occurs postnatally in mainly in premature and low birth weight infants (1 in 2,000 - 4,000 births). The underdeveloped gastointestinal tract appears to be susceptible to bacteria, normally found within the tract,to spread widely to other regions where they damage the tract wall and may enter the bloodstream.

Stillbirth and Perinatal Death

World neonatal death.jpg
NSW perinatal mortality rate

Perinatal period is the early postnatal period relating to the birth, statistically it includes the period up to 7 days after birth. Neonatal period is the four weeks/month after birth. Stillbirth and Perinatal Death

In New South Wales (2002) 613 perinatal deaths were reported.

  • Unexplained antepartum deaths: 26.3% of perinatal deaths (or 39.2% of stillbirths)
  • Spontaneous preterm labour: 20.6% (less than 37 weeks gestation)
  • Congenital abnormality: 16.8%
  • Antepartum haemorrhage: 8.5%
  • Specific perinatal conditions: 7.3%, of which twin-twin transfusion accounted for 2.3% of deaths
  • Hypertension (high blood pressure): 5.5%
  • Perinatal infection: 4.4%
  • Maternal disease: 4.4%
  • Hypoxic peripartum death: 3.8%

Neonatal deaths (four weeks/month after birth)

  • extreme prematurity was most common cause (39.6%)
  • congenital abnormality (19.3%)
  • neurological disease (13.4%)
  • cardio-respiratory conditions (11.9%)
  • infection (8.4%)

Data: Report of the New South Wales Chief Health Officer, 2004 accessed 19Oct05

Links

Birth Terms

amniotomy - birth medical procedure thought to speed labor, where the amniotic sac is artificially ruptured using a tool (amniohook).

breech - fetal buttocks presented first and can also occur in different forms depending on presentation (complete breech, frank breech, footing breech, knee breech).

decidual activation - increased uterine proteolysis and extracellular matrix degradation.

dilatation - opening of the cervix in preparation for birth (expressed in centimetres).

effacement - shortening or thinning of the cervix, in preparation for birth.

forceps - mechanical "plier-like" tool used on fetal head to aid birth.

fetal macrosomia - clinical description for a fetus that is too large, condition increases steadily with advancing gestational age and defined by a variety of birthweights. In pregnant women anywhere between 2 - 15% have birth weights of greater than 4000 grams (4 Kg, 8 lb 13 oz).

membrane rupture - breaking of the amniotic membrane and release of amniotic fluid (water breaking).

morbidity - (Latin, morbidus = "sick" or "unhealthy") refers to a diseased state, disability, or poor health due to any cause.

presentation - how the fetus is situated in the uterus.

presenting part - part of fetus body that is closest to the cervix.

second stage of labour - passage of the baby through the birth canal into the outside world.

Vacuum Extractor - suction cap device used on fetal head to aid birth.

Vertex Presentation (cephalic presentation) where the fetus head is the presenting part, most common and safest birth position.



Vaginal delivery of breech presentation.

Kotaska A, Menticoglou S, Gagnon R, Farine D, Basso M, Bos H, Delisle MF, Grabowska K, Hudon L, Mundle W, Murphy-Kaulbeck L, Ouellet A, Pressey T, Roggensack A; Maternal Fetal Medicine Committee; Society of Obstetricians and Gynaecologists of Canada. J Obstet Gynaecol Can. 2009 Jun;31(6):557-66, 567-78. English, French. PMID: 19646324


Birth Weight Conversion

  • Extremely Low Birth Weight (ELBW)
    • Less than 500 grams
    • 500 – 999 grams
  • Very Low Birth Weight (VLBW)
    • 1,000 – 1,499 grams
  • Low Birth Weight (LBW)
    • 1,500–1,999 grams
    • 2,000–2,499 grams
  • Normal Birth Weight
    • 2,500–2,999 grams
    • 3,000–3,499 grams
    • 3,500–3,999 grams
  • High Birth Weight (macrosomia)
    • 4,000–4,499 grams
    • 4,500–4,999 grams
    • 5,000 grams or more


Less than 500 grams=1 lb 1 oz or less

500–999 grams = 1lb2oz–2lb3oz

1,000–1,499 grams = 2 lb 4 oz–3 lb 4 oz

1,500–1,999 grams = 3 lb 5 oz–4 lb 6 oz

2,000–2,499 grams = 4 lb 7 oz–5 lb 8 oz

2,500–2,999 grams = 5 lb 9 oz–6 lb 9 oz

3,000–3,499 grams = 6 lb 10 oz–7 lb 11 oz

3,500–3,999 grams = 7 lb 12 oz–8 lb 13 oz

4,000–4,499 grams = 8 lb 14 oz–9 lb 14 oz

4,500–4,999 grams = 9 lb 15 oz–11 lb 0 oz

5,000 grams or more = 11 lb 1 oz or more

Macrosomia

  • large size of parents (especially the mother)
  • multiparity diabetes in the mother
  • prolonged gestation
  • older maternal age
  • male infants
  • previous delivery of a high birthweight infant


Gestation

from same USA report

The primary measure used to determine the gestational age of the newborn is the interval between the first day of the mother’s last normal menstrual period (LMP) and the date of birth. It is subject to error for several reasons, including imperfect maternal recall or misidentification of the LMP because of post conception bleeding, delayed ovulation, or intervening early miscarriage.

The U.S. Standard Certificate of Live Birth includes an item, ‘‘clinical/obstetric estimate of gestation,’’ that was compared with length of gestation computed from the date the last normal menstrual period (LMP) began when the latter appeared to be inconsistent with birth- weight.


USA Births: Final Data for 2006

  • In 2006, the number of births and birth and fertility rates increased for nearly all age groups, live-birth orders, race, and Hispanic origin groups and reporting areas. In some cases, rates rose to levels not seen in three or more decades.
  • A total of 4,265,555 births were registered in the United States in 2006, 3 percent higher than in 2005. This is the largest single-year increase in births since 1989 and the largest number since 1961. Births increased for all race and Hispanic origin groups between 2005 and 2006.
  • The crude birth rate for the U.S. was 14.2 live births per 1,000 persons in 2006, up slightly from 2005. The general fertility rate was 68.5 births per 1,000 women aged 15–44 years, an increase of 3 percent over 2005 and the highest rate reported since 1991. Fertility rates for nearly all race and Hispanic origin groups increased.
  • Birth rates increased for women of most age groups between 2005 and 2006. The only exceptions were the youngest mothers (under age 15 years) for whom the rate declined slightly, and mothers aged 45–49 years, for whom the birth rate was unchanged.
  • The birth rate for teenagers 15–19 years increased 3 percent in 2006, interrupting the 14-year period of continuous decline from 1991 through 2005. Only the rate for the youngest adolescents declined in 2006, to 0.6 per 1,000 aged 10–14 years. Rates for teenagers 15–17 and 18–19 years rose 3 to 4 percent each. These increases follow declines of 45 and 26 percent, respectively, in the rates between 1991 and 2005. Between 2005 and 2006, birth rates increased 3 to 5 percent each for non-Hispanic white, non- Hispanic black, and American Indian or Alaska Native teenagers and 2 percent for Hispanic teenagers. The rate for Asian or Pacific Islander teenagers was unchanged. Teenage birth rates increased significantly between 2005 and 2006 in 26 states, representing nearly every region of the country.
  • The first birth rate for women aged 15–44 years increased 3 percent to 27.4 births per 1,000 women. First birth rates increased for nearly all age groups.
  • Labor was induced for 22.5 percent of births in 2006, a slight increase over 2005, and double the rate for 1990. Induction rates are up substantially for all gestational ages, including preterm births, since 1990.
  • The cesarean delivery rate rose 3 percent to 31.1 percent of all births, another record high. The cesarean rate has climbed 50 per­ cent since the 1996 low. Rates for primary cesareans were up and vaginal births after previous cesarean were down for both revised and unrevised reporting areas. Cesarean rates have risen at all gestational ages over the last decade.
  • The preterm birth rate rose again in 2006 to 12.8 percent of all births. The percentage of infants delivered at less than 37 com­ pleted weeks of gestation has climbed 20 percent since 1990. Most of this rise is attributable to the increases in late preterm births (34–36 weeks), up 25 percent since 1990. Preterm birth rates rose slightly for Hispanic infants, but were unchanged among non-Hispanic white and non-Hispanic black infants. The singleton preterm rate also increased in 2006, to 11.1 percent. This rate has climbed 14 percent since 1990.
  • The low birthweight (LBW) rate also continued to rise, climbing to 8.3 percent in 2006, the highest level in four decades. The percentage of infants born at less than 2,500 grams has risen 19 percent since 1990. All of the rise for 2005–2006 was among moderately LBW (1,500–2,499 grams) infants. LBW rates rose slightly for Hispanic infants, but were unchanged for non-Hispanic white and non-Hispanic black infants. The LBW rate for infants born in single deliveries also increased in 2006; singleton LBW has risen 10 percent since 1990.
  • The rapid rise in multiple birth rates over the last several decades may have ended. The 2006 twin birth rate (32.1 twins per 1,000 births) remained essentially unchanged from 2005. The twin birth rate climbed 70 percent between 1980 and 2004. The triplet plus/+ birth rate declined 5 percent for 2005–2006, to 153.3 per 100,000 total births. This rate soared more than 400 percent between 1980 and 1998, but is down 21 percent since then.


Martin JA, Hamilton BE, Sutton PD, Ventura SJ, et al. Births: Final data for 2006. National vital statistics reports; vol 57 no 7. Hyattsville, MD: National Center for Health Statistics. 2009. National vital statistics reports; vol 57 no 7 PDF

Copyright information - All material appearing in this report is in the public domain and may be reproduced or copied without permission; citation as to source, however, is appreciated.

data file download

VitalStats - is a A new data access and analysis tool VitalStats

National Vital Statistics Reports [1]

VitalStats Perinatal Mortality (USA)

http://www.cdc.gov/nchs/data_access/vitalstats/VitalStats_Perinatal_Mortality.htm

"Notice of Error in the 2003 and 2004 Fetal Death Data Files and Reports, and Instructions for Correcting the Data File Error

Due to a programming error, the Tabulation Flag variable located in position 9 is incorrect in the 2003 and 2004 fetal death data files. This variable identifies fetal deaths of stated or presumed period of gestation of either <20 weeks, or 20 weeks or more. Most tabulations and reports of fetal death data include only fetal deaths of 20 weeks of gestation or more. Due to this error, some fetal death records with not stated gestational ages that should have been included in the 20 weeks or more group were erroneously assigned to the <20 week group. This led to a slight underestimate of fetal mortality rates published in the National Vital Statistics Reports: Fetal and Perinatal Mortality, United States, 2003 and Fetal and Perinatal Mortality, United States, 2004. The documentation tables published in the Fetal Death User’s Guides for 2003 and 2004 are also incorrect. Tables 1 and 2 below show the effect of correcting this error on fetal and perinatal mortality rates. It should be emphasized that although the corrected rates are a bit different from those originally published, they are not statistically different in that the statements about statistical significance or lack thereof made in the fetal and perinatal reports for 2003-2005 did not change. In other words, the US fetal mortality rate did not decline significantly from 2002-03, 2003-04, 2004-05, or 2003-05. There was a significant decline in the fetal mortality rate from 2002-04 and 2002-05. In the vast majority of the states, the corrected numbers differed from the originally reported numbers by less than 1.0 percent in each year (Tables 2 and 3)."

USA Weight Gain in Pregnancy

In 1990, the Institute of Medicine (IOM) issued recommendations for gestational weight gain (43). These guidelines are based on the mother’s body mass index (BMI), which takes into account both the mother’s height and weight.

A recent workshop held by the IOM and National Academy of Sciences developed a research agenda empha­ sizing the need to make specific recommendations for subgroups such as: adolescent mothers, mothers in diverse racial and ethnic groups, and mothers carrying twins or higher order multiples (44).

2006 Data

  • 13 percent of all mothers gained less than 16 pounds (considered inadequate for most women)
  • 21 percent had weight gains of more than 40 pounds (considered excessive for all women).
  • approximately one-third of all mothers had weight gains outside of the guidelines, regardless of their height.

reference

Maternal age and diabetes risk

  • diabetes rate for mothers 40 years of age and over was 94.3 per 1,000 (2006)
    • 6 times higher than that for mothers under 20 years of age (13.3 per 1,000).
  • Diabetes rates also differ by maternal race and ethnicity
    • highest for API mothers (7.1 percent)
    • AIAN (6.4 percent)
    • Hispanic (4.3percent) Hispanic subgroups, percent­ ages ranged from 4.0 for Cuban to 4.9 for Puerto Rican mothers.
    • non-Hispanic white (4.0percent)
    • non-Hispanic black mothers (3.7 percent)

Smoking During Pregnancy

  • overall smoking rate was 13.2 percent
    • For the 17 states for which revised information on tobacco use is available for 2006