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Labor and Delivery: Research Activities and Scientific Advances

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Through its intramural and extramural organizational units, the NICHD supports and conducts a broad range of research projects on labor and delivery. Short descriptions of this research are included below.

Institute Activities and Advances

Division of Extramural Research (DER)

Several organizational units within the DER support research on labor and delivery:

The Pregnancy and Perinatology Branch (PPB) seeks to improve the health of mothers and children by supporting research in several areas related to pregnancy, including labor and delivery. PPB-supported studies are examining the adverse effects of oxytocin receptor desensitization due to prolonged oxytocin infusion during labor induction; molecular mechanisms of uterine contractions during normal labor, preterm labor, and post-term pregnancies; neural regulation of pre-partum cervical ripening; comparative effectiveness of antibiotics for cesarean delivery; development of improved labor diagnostic devices; obstetrical determinants of neonatal survival; and labor induction versus expectant management in post-term pregnancy.

The Obstetric and Pediatric Pharmacology and Therapeutics Branch (OPPTB) supports research with the goal of increasing the knowledge base for understanding how to appropriately use various pharmaceuticals during pregnancy, including medications commonly used during labor and delivery.

The Maternal and Pediatric Infectious Disease Branch (MPIDB) supports and conducts a wide range of domestic and international research related to the epidemiology, diagnosis, clinical manifestations, pathogenesis, transmission, treatment, and prevention of HIV infection and its associated infectious complications (such as tuberculosis, malaria, and hepatitis) and non-infectious complications in pregnant and non-pregnant women, infants, children, adolescents, and the family unit as a whole.

  • MPIDB-supported findings: A recent MPIDB-supported study found that infants born to women who used the anti-HIV drug tenofovir as part of an anti-HIV drug regimen during pregnancy do not weigh less at birth and are not of shorter length than infants born to women who used anti-HIV drug regimens that do not include tenofovir during pregnancy. However, at 1 year of age, children born to the tenofovir-treated mothers were slightly shorter and had slightly smaller head circumference—about 1 centimeter each, on average—than infants whose mothers did not take tenofovir. The study authors described the findings as reassuring, because the study did not identify any serious safety concerns for tenofovir during pregnancy.

Another study examined the pharmacokinetics and placental transfer of single-dose tenofovir vaginal gel in term pregnancy. The International Maternal, Pediatric, Adolescent AIDS Clinical Trials (IMPAACT) Network is a cooperative group of institutions, investigators, and other collaborators focused on evaluating potential therapies for HIV infection and its related symptoms in infants, children, adolescents, and pregnant women, including clinical trials of HIV/AIDS interventions for and prevention of mother-to-child transmission. The IMPAACT Network collaborates with the NICHD Domestic and International Pediatric and Maternal HIV Clinical Studies Network, which conducts trials related to preventing and treating HIV infection and its complications in newborns, infants, children, adolescents, and pregnant women.

The Population Dynamics Branch supports research on demography, reproductive health, and population health. Current studies are examining mode of first delivery on subsequent childbearing and the role of prenatal employment in health care choices and services during childbirth.

Division of Intramural Population Health Research (DIPHR)

DIPHR conducts research to identify critical data gaps and designs research initiatives to answer etiologic questions or to evaluate interventions aimed at modifying behavior related to public health.

The Consortium on Safe Labor (CSL), led by researchers within the DIPHR’s Epidemiology Branch, was an observational study whose goals were to explore the underlying causes of the high cesarean rate in the U.S. population; describe contemporary labor progression at the national level; determine when is the most appropriate time to perform a cesarean delivery in women with labor protraction and arrest; and examine air quality and its effect on reproductive health and birth outcomes.

  • DIPHR research findings: Representing a consortium of 12 clinical centers with 228,562 pregnancies across the United States, the CSL team identified several key findings regarding contemporary obstetric management. These included:
    • The team identified factors contributing to the high national cesarean delivery rate: One out of three first-time mothers delivered by cesarean; a high percentage of intrapartum cesarean deliveries were performed too soon, before women achieved active labor; and prelabor repeat cesarean delivery was the most common reason for cesarean section. (PMID: 20708166)
    • Women spend longer in labor now than approximately 50 years ago. The implication of this finding is that preventing cesarean delivery in the first pregnancy will go a long way to decrease the national cesarean delivery rate. Because providers are using definitions of abnormal labor developed in a population of women different from the contemporary obstetrical population, the CSL findings suggest that routine interventions, such as the use of oxytocin and timing of cesarean delivery, as well as modern-day labor process management warrant reconsideration. (PMID: 21099592, PMID: 22542117)
    • A prolonged second stage of labor was associated with highly successful vaginal delivery rates but also with small increases in maternal and serious neonatal morbidity, as well as perinatal mortality in deliveries without an epidural. Investigators assessed neonatal and maternal outcomes when the second stage—the time from when pushing begins until delivery of the baby—was prolonged, according to American College of Obstetricians and Gynecologists (ACOG) guidelines. The findings suggest that benefits of vaginal delivery need to be weighed against increased maternal and neonatal risks when second-stage labor lasts longer than outlined in the ACOG guidelines. (PMID: 24901265)

Other areas of ongoing research include determining the optimal time for the second stage of labor and exploring how sociodemographic changes in the current obstetrical population have affected pregnancy complications; maternal and neonatal morbidity; and implications for clinical management, including delivery timing and route. Researchers are also exploring how chronic diseases, such as hypertension, diabetes, and asthma, affect these outcomes. Further work from the CSL study will help shape the future clinical care of pregnant women.

Division of Intramural Research (DIR)

The Program in Perinatal Research and Obstetrics (PPRO) within the DIR conducts clinical and laboratory research on maternal and fetal diseases responsible for excessive infant mortality in the United States. The PPRO focuses on the mechanisms of disease responsible for premature labor and delivery, with particular emphasis on the role of subclinical intrauterine infection and inflammation. The prenatal diagnosis of congenital anomalies is also a major area of interest. Current research is exploring the prognostic value of angiogenic factors in patients with suspected preeclampsia and the effects of vaginal progesterone on risk of preterm birth and associated neonatal complications in women with a short cervix.

The NICHD’s research related to preterm labor and birth is covered in the preterm labor and birth topic.

Other Activities and Advances

  • Maternal-Fetal Medicine Units (MFMU) Network
    This PPB-funded network was established in 1986 to respond to the need for well-designed clinical trials in maternal-fetal medicine and obstetrics, particularly on preterm birth. The MFMU Network is currently studying whether giving steroids just before preterm birth could help babies breathe; transmission of the hepatitis C virus from mother to baby; and STAN (ST Segment and T Wave Analysis), a new method for fetal heart monitoring.
  • Obstetric-Fetal Pharmacology Research Unit (OPRU) Network
    The OPPTB-supported OPRU Network provides the expert infrastructure needed to test therapeutic drugs during pregnancy. Current OPRU Network studies are investigating medications to alter uterine activity, such as those used to delay or prevent preterm birth; molecular and cellular mechanisms of changes in fetal membranes during labor at term; and distribution of the antidepressant bupropion and its metabolites in the maternal vein, umbilical cord, and placental tissue.
  • Global Network for Women’s and Children’s Health Research
    This network is a partnership committed to improving maternal and infant health outcomes and building health research capacity in resource-poor settings by testing cost-effective, sustainable interventions. The Network’s efforts include evaluating training programs for emergency obstetric care and examining drug treatments for high-risk pregnancies. Other studies are addressing improvements in perinatal care in Latin America; assessing the use of misoprostol for prevention of postpartum hemorrhage in India; investigating ways to reduce infection-related perinatal mortality in Pakistan; and evaluating effectiveness of a health worker training program in essential newborn care and resuscitation to prevent newborn death from asphyxiation.
  • National Child and Maternal Health Education Program (NCMHEP)
    The NCMHEP Is It Worth It? Initiative describes the benefits to mother and baby of waiting until at least 39 weeks of pregnancy to deliver, unless it is medically necessary to deliver earlier. The newly launched Know Your Terms Initiative explains the recent changes in the definition of full term.
  • NIH Consensus Development Conferences
    For these conferences, independent panels of health professionals and public representatives prepared consensus and state-of-the-science statements based on results of a systematic literature review.

Research activities and scientific advances in the area of preterm labor and delivery are listed in the preterm labor and birth topic.

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