The United States has a shorter average pregnancy duration compared to Europe

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In the United States, where mother and newborn mortality rates are far higher than in Europe and other developed countries, maternal health outcomes continue to worsen. Researchers from Boston University School of Public Health (BUSPH) and the Beth Israel Deaconess Medical Center (BIDMC), which is affiliated with Harvard Medical School, are leading a new study that sheds light on how hospital organizational structures and staffing within US maternity care may impact the birthing process and potentially contribute to unfavorable birth outcomes.

The study, which was published in the journal PLOS ONE, examined the gestational age distribution and timing of home and hospital births in three high-income nations: the US, which follows a model of maternity care that mainly depends on obstetricians and clinical interventions, and England and the Netherlands, which rely mainly on midwives who offer low-intervention maternity care.

The study demonstrates that US pregnancies, on average, are shorter than pregnancies in England and the Netherlands, and that the average length of US pregnancies continuously decreased by more than half a week between 1990 and 2020, from 39.1 weeks to 38.5 weeks. Compared to 44 percent of births in the Netherlands and 40 percent of births in England, just 23 percent of US births took place at 40 weeks or more in 2020. In all three nations, the gestational age distribution for in-home deliveries was the same.

The researchers limited the study to hospital-based vaginal deliveries without procedures like induction or labor augmentation that might potentially change the timing. They also looked at the birth time by hour of the day for home and hospital-based vaginal births in all three nations.

Births at home and in hospitals were placed at comparable periods of the day in England and the Netherlands, peaking between one and six in the morning.

The timing of births in the US, however, was noticeably different between the two settings: home births peaked at the same time as home births in other nations. Conversely, hospital-based births—even those without interventions that would have changed the normal pattern of timing—most frequently took place between 8 a.m. to 5 p.m., the usual workday for clinical personnel.

The publication is the first international study comparing gestational age and birth timing in three high-income countries utilizing big datasets; the majority of other studies have concentrated on data from specific hospitals or nations. The authors claim their findings indicate the US maternity care models might benefit from an organizational change that places less focus on active, clinical management of labor and allows the birthing process to take a natural course. This is because England and the Netherlands have better birthing outcomes than the US.

According to Dr. Eugene Declercq, professor of community health sciences at BUSPH and research leader, this multi-country analysis demonstrates that the US is an exception in gestational age distribution and timing of low-intervention hospital deliveries.  Hospital staffing and operational strategies should more closely follow the natural patterns of birth timing and gestational age rather than attempting to make birth timing match organizational demands, according to nations with better maternity outcomes than the US.

The study examined population-based birth data from all three nations that were publicly available and nationally representative, including information on more than 3.8 million births in the US, 156,000 births in the Netherlands in 2014, and more than 56,000 births in England between 2008 and 2010. For births that took place between 37 and 42 weeks, the researchers compared the timing of births at home and in hospitals.

According to study senior author Dr. Neel Shah, chief medical officer of Maven Clinic and a visiting scientist at BIDMC, every system is ideally built to produce the results that it gets. The maternal health system in the US has to be designed with more consideration given to its disturbingly low outcomes. The research demonstrates that American hospitals may be built with the convenience of doctors and nurses in consideration more so than the needs of women giving birth when compared to other high-income nations.


Declercq E, Wolterink A, Rowe R, de Jonge A, De Vries R, Nieuwenhuijze M, et al. (2023) The natural pattern of birth timing and gestational age in the U.S. compared to England, and the Netherlands. PLoS ONE 18(1): e0278856.