Talk:Birth

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Cite this page: Hill, M.A. (2024, March 28) Embryology Birth. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Talk:Birth



Gestation

  • 40 weeks from the last normal menstrual period (LNMP).
  • 37 weeks and 42 weeks World Health Organization defines normal term.

2012

Amniotic fluid embolism incidence, risk factors and outcomes: a review and recommendations

BMC Pregnancy Childbirth. 2012 Feb 10;12:7.

Knight M, Berg C, Brocklehurst P, Kramer M, Lewis G, Oats J, Roberts CL, Spong C, Sullivan E, van Roosmalen J, Zwart J. Source National Perinatal Epidemiology Unit, University of Oxford, Oxford, UK. marian.knight@npeu.ox.ac.uk

Abstract

BACKGROUND: Amniotic fluid embolism (AFE) is a rare but severe complication of pregnancy. A recent systematic review highlighted apparent differences in the incidence, with studies estimating the incidence of AFE to be more than three times higher in North America than Europe. The aim of this study was to examine population-based regional or national data from five high-resource countries in order to investigate incidence, risk factors and outcomes of AFE and to investigate whether any variation identified could be ascribed to methodological differences between the studies. METHODS: We reviewed available data sources on the incidence of AFE in Australia, Canada, the Netherlands, the United Kingdom and the USA. Where information was available, the risk factors and outcomes of AFE were examined. RESULTS: The reported incidence of AFE ranged from 1.9 cases per 100 000 maternities (UK) to 6.1 per 100 000 maternities (Australia). There was a clear distinction between rates estimated using different methodologies. The lowest estimated incidence rates were obtained through validated case identification (range 1.9-2.5 cases per 100 000 maternities); rates obtained from retrospective analysis of population discharge databases were significantly higher (range 5.5-6.1 per 100 000 admissions with delivery diagnosis). Older maternal age and induction of labour were consistently associated with AFE. CONCLUSIONS: Recommendation 1: Comparisons of AFE incidence estimates should be restricted to studies using similar methodology. The recommended approaches would be either population-based database studies using additional criteria to exclude false positive cases, or tailored data collection using existing specific population-based systems.Recommendation 2: Comparisons of AFE incidence between and within countries would be facilitated by development of an agreed case definition and an agreed set of criteria to minimise inclusion of false positive cases for database studies.Recommendation 3: Groups conducting detailed population-based studies on AFE should develop an agreed strategy to allow combined analysis of data obtained using consistent methodologies in order to identify potentially modifiable risk factors.Recommendation 4: Future specific studies on AFE should aim to collect information on management and longer-term outcomes for both mothers and infants in order to guide best practice, counselling and service planning.

PMID 22325370

2011

Methods of induction of labour: a systematic review

BMC Pregnancy Childbirth. 2011 Oct 27;11:84.

Mozurkewich EL, Chilimigras JL, Berman DR, Perni UC, Romero VC, King VJ, Keeton KL. Source Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, University of Michigan, 1500 E, Medical Center Drive, Ann Arbor, MI 48109-0264, USA. mozurk@umich.edu

Abstract

BACKGROUND: Rates of labour induction are increasing. We conducted this systematic review to assess the evidence supporting use of each method of labour induction. METHODS: We listed methods of labour induction then reviewed the evidence supporting each. We searched MEDLINE and the Cochrane Library between 1980 and November 2010 using multiple terms and combinations, including labor, induced/or induction of labor, prostaglandin or prostaglandins, misoprostol, Cytotec, 16,16,-dimethylprostaglandin E2 or E2, dinoprostone; Prepidil, Cervidil, Dinoprost, Carboprost or hemabate; prostin, oxytocin, misoprostol, membrane sweeping or membrane stripping, amniotomy, balloon catheter or Foley catheter, hygroscopic dilators, laminaria, dilapan, saline injection, nipple stimulation, intercourse, acupuncture, castor oil, herbs. We performed a best evidence review of the literature supporting each method. We identified 2048 abstracts and reviewed 283 full text articles. We preferentially included high quality systematic reviews or large randomised trials. Where no such studies existed, we included the best evidence available from smaller randomised or quasi-randomised trials. RESULTS: We included 46 full text articles. We assigned a quality rating to each included article and a strength of evidence rating to each body of literature. Prostaglandin E2 (PGE2) and vaginal misoprostol were more effective than oxytocin in bringing about vaginal delivery within 24 hours but were associated with more uterine hyperstimulation. Mechanical methods reduced uterine hyperstimulation compared with PGE2 and misoprostol, but increased maternal and neonatal infectious morbidity compared with other methods. Membrane sweeping reduced post-term gestations. Most included studies were too small to evaluate risk for rare adverse outcomes. CONCLUSIONS: Research is needed to determine benefits and harms of many induction methods.

PMID 22032440

Vitamin A and E status in very low birth weight infants

J Perinatol. 2011 Jul;31(7):471-6. doi: 10.1038/jp.2010.155. Epub 2011 Jan 13.

Kositamongkol S, Suthutvoravut U, Chongviriyaphan N, Feungpean B, Nuntnarumit P. Source Department of Pediatrics, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.

Abstract

Objective:To determine vitamin A and vitamin E status in very low birth weight (VLBW) infants at the time of birth (TB), at the time of full feeding (TFF) and at term postmenstrual age (TT).Study Design:An observational study was conducted in VLBW infants. Plasma retinol and α-tocopherol levels were measured at TB, TFF and TT. Multivitamin supplementation was given to all infants to meet the daily requirement.Result:A total of 35 infants were enrolled. The median (interquartile range) of gestational age and birth weight was 30 (28 to 32) weeks and 1157 g (982 to 1406 g). The median of vitamin A and vitamin E intakes from TFF to TT was 832 and 5.5 IU kg(-1) day(-1), respectively. Vitamin A deficiency occurred in 67.7% at birth, 51.6% at TFF and 82.1% at TT. Vitamin E deficiency occurred in 77.4% at birth, 16.1% at TFF and 35.7% at TT. Small-for-gestational age was the only risk factor for vitamin A deficiency. Lower amount of breast milk consumption was associated with higher incidence of vitamin E deficiency. No differences in vitamin A- or vitamin E-related morbidities between infants with and without vitamin deficiencies were found.Conclusion:High prevalence of vitamin A and vitamin E deficiency was found in VLBW infants starting from birth to term postmenstrual age. Therefore, a higher dose of vitamin supplementation is required.

PMID: 21233795 http://www.ncbi.nlm.nih.gov/pubmed/21233795

2010

Regulation of vascular tone and remodeling of the ductus arteriosus

J Smooth Muscle Res. 2010;46(2):77-87.

Yokoyama U, Minamisawa S, Ishikawa Y. Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine. utako@yokohama-cu.ac.jp Abstract

The ductus arteriosus (DA), a fetal arterial connection between the main pulmonary artery and the descending aorta, normally closes immediately after birth. The DA is a normal and essential fetal structure. However, it becomes abnormal if it remains patent after birth. Closure of the DA occurs in two phases: functional closure of the lumen within the first hours after birth by smooth muscle constriction, and anatomic occlusion of the lumen over the next several days due to extensive neointimal thickening in human DA. There are several events that promote the DA constriction immediately after birth: (a) an increase in arterial oxygen tension, (b) a dramatic decline in circulating prostaglandinE(2) (PGE(2)), (c) a decrease in blood pressure within the DA lumen, and (d) a decrease in the number of PGE(2) receptors in the DA wall. Anatomical closure of the DA is associated with the formation of intimal thickening, which are characterized by (a) an area of subendothelial deposition of extracellular matrix, (b) the disassembly of the internal elastic lamina and loss of elastic fiber in the medial layer, and (c) migration into the subendothelial space of undifferentiated medial smooth muscle cells. In addition to the well-known vasodilatory role of PGE(2), our findings uncovered the role of PGE(2) in anatomical closure of the DA. Chronic PGE(2)-EP4-cyclic AMP (cAMP)-protein kinase A (PKA) signaling during gestation induces vascular remodeling of the DA to promote hyaluronan-mediated intimal thickening and structural closure of the vascular lumen. A novel target of cAMP, Epac, has an acute promoting effect on smooth muscle cell migration without hyaluronan production and thus intimal thickening in the DA. Both EP4-cAMP downstream targets, Epac and PKA, regulate vascular remodeling in the DA. PMID: 20551589


Are babies getting bigger? An analysis of birthweight trends in New South Wales, 1990-2005

Hadfield RM, Lain SJ, Simpson JM, Ford JB, Raynes-Greenow CH, Morris JM, Roberts CL. Med J Aust. 2009 Mar 16;190(6):312-5. PMID: 19296812

OBJECTIVE: To determine whether the proportion of babies born large for gestational age (LGA) in New South Wales has increased, and to identify possible reasons for any increase.

DESIGN AND SETTING: Population-based study using data obtained from the NSW Midwives Data Collection, a legislated surveillance system of all births in NSW.

PARTICIPANTS: All 1 273 924 live-born singletons delivered at term (> or = 37 complete weeks' gestation) in NSW from 1990 to 2005.

MAIN OUTCOME MEASURES: LGA, defined as > 90th centile for sex and gestational age using 1991-1994 Australian centile charts; maternal factors associated with LGA were assessed using logistic regression.

RESULTS: The proportion of babies born LGA increased from 9.2% to 10.8% (18% increase) for male infants and from 9.1% to 11.0% (21% increase) for female infants. The mean birthweight increased by 23 g for boys and 25 g for girls over the study period. Increasing maternal age, higher rates of gestational diabetes and a decline in smoking contributed significantly to these increases, but did not fully explain them.

CONCLUSIONS: There is an increasing trend in the proportion of babies born LGA, which is only partly attributable to decreasing maternal smoking, increasing maternal age and increasing gestational diabetes.

eMJA

Invited review: Clearance of lung liquid during the perinatal period

J Appl Physiol. 2002 Oct;93(4):1542-8.

Barker PM, Olver RE.

Department of Pediatrics, University of North Carolina, Chapel Hill, North Carolina 27599-7220, USA. pbarker@med.unc.edu

Abstract At birth, the distal lung epithelium undergoes a profound phenotypic switch from secretion to absorption in the course of adaptation to air breathing. In this review, we describe the developmental regulation of key membrane transport proteins and the way in which epinephrine, oxygen, glucocorticoids, and thyroid hormones interact to bring about this crucial change in function. Evidence from molecular, transgenic, cell culture, and whole lung studies is presented, and the clinical consequences of the failure of the physiological mechanisms that underlie perinatal lung liquid absorption are discussed.

PMID: 12235057

http://www.ncbi.nlm.nih.gov/pubmed/12235057

http://jap.physiology.org/cgi/content/full/93/4/1542

Birth lecture

Links

Nurse - Midwifery Utah

http://library.med.utah.edu/nmw/mod2/Tutorial2/anatomy.html


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


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

Macrosomia

Performance of 36 different weight estimation formulae in fetuses with macrosomia

Hoopmann M, Abele H, Wagner N, Wallwiener D, Kagan KO. Fetal Diagn Ther. 2010 Jul;27(4):204-13. Epub 2010 Jun 3.

Ultrasound estimation of fetal weight (FW) was carried out within 7 days up to delivery in 350 singleton fetuses with a birth weight (BW) of >or=4,000 g. The accuracy of the different formulae for FW estimation was compared by, firstly, the mean percentage (MPE) and mean absolute percentage error (MAPE), secondly, by the frequency distribution of differences between estimated FW and fetal BW, and thirdly by comparing detection and false positive rates in screening for fetuses with a BW of 4,000, 4,300 and 4,500 g or more.

RESULTS: MPE ranged from -62.2 to 9.6% and was closest to 0 with the Hart formula. With 12 of 36 weight estimation formulae, MAPE was 10% or less, and was smallest with the Hart formulae (3.9%). The mean detection rate among all formulae for fetuses with a BW >or=4,000, >or=4,300 and >or=4,500 g was 29, 24 and 22%, respectively, and the false positive rate was 12% (for >or=4,300 g) and 7% (>or=4,500 g).

DISCUSSION: Some formulae showed advantages as far as mean and absolute percentage errors were concerned, but none reached a detection rate and false positive rate for fetuses >or=4,500 g that could lead to clinical recommendation.

PMID: 20523027 http://www.ncbi.nlm.nih.gov/pubmed/20523027