A new, multi-country analysis examining average pregnancy length and timing of birth in the US, England, and the Netherlands suggest that the US could improve maternity care outcomes by shifting from an interventionist model of care to one that favours less medical intervention during the birthing process. 

Maternal health outcomes continue to worsen in the United States, where maternal and infant mortality rates far exceed rates in European countries and other wealthy nations. Now, a new study from Amsterdam UMC, together with Boston University School of Public Health (BUSPH), Oxford University and Harvard Medical School sheds light on how hospital organisational structures and staffing within US maternity care may affect the birthing process and possibly contribute to adverse birth outcomes.  

Published in the journal PLOS One, the study analysed gestational age patterns and timing of home and hospital births in three high-income countries with two different approaches to maternity care. 

“The differences are rather stark. In the U.S., they have a model that is way more dependent on gynaecologists whereas in the Netherlands and in the UK, most births are attended by midwives,” says Ank de Jonge, Professor of Midwifery Science at Amsterdam UMC. “The U.S. model relies much more on medical interventions than the model in the UK and the Netherlands.”  

The findings showed that the average length of US pregnancies steadily declined by more than half a week between 1990 and 2020, from 39.1 weeks to 38.5 weeks, and that US pregnancies on average are shorter than pregnancies in England and the Netherlands. In 2020, only 23 percent of US births occurred at 40 or more weeks, compared to 44 percent of births in the Netherlands and 40 percent of births in England. The gestational age pattern for home births was the same in all three countries.  

In all three countries, the researchers also examined birth timing by hour of the day for home and vaginal births at the hospital, and then repeated this analysis, limiting the comparison to hospital-based vaginal births without interventions such as induction or labour augmentation that could possibly alter the timing. 

In England and the Netherlands, births at home and at the hospital occurred at similar times in the day, peaking in the early morning hours between 1 a.m.-6 a.m. 

But in the US, there was a noticeable difference in birth timing between the two settings: births at home peaked in the same early morning hours as home births in other countries, while the hospital-based births—even those with no interventions that could affect the natural pattern of timing—largely occurred during standard working hours for clinical staff, from 8 a.m. to 5 p.m. 

For de Jonge, this is logical but perhaps not exactly understandable: “interventions, such as and induced birth or a caesarean section are planned during the day. You also have simply more staff in the hospital. But, if you look at the police for example, they often have more people at night because they know that’s when all hell is going to break loose.” 

The paper is the first international study to utilize large datasets to compare gestational age and birth timing in three high-income countries; most prior research has focused on data from individual hospitals or countries. As England and the Netherlands have better birthing outcomes than the US, the findings suggest that the US maternity care models could benefit from an organizational shift that places less emphasis on active, clinical management of labour and allows the birthing process to take a natural course.  

“Our multi-country analysis shows that the US is an outlier in gestational age distribution and timing of low-intervention hospital births,” says study lead and corresponding author Dr. Eugene Declercq, professor of community health sciences at BUSPH. “There’s a lesson to be learned from countries with more positive maternity outcomes than the US in having hospital staffing and operational plans conform more closely to the natural patterns of birth timing and gestational age rather than try to have birth timing fit organizational needs.” 

The study included nationally representative and publicly available population-based birth data from all three countries, including data on more than 3.8 million births in the US and 156,000 births in the Netherlands in 2014, and more than 56,000 births in England from 2008-2010. The researchers examined home and hospital birth timing for births that occurred between 37 and 42 weeks. 

“Every system is perfectly designed to get the results that it gets,” says study senior author Dr. Neel Shah, chief medical officer of Maven Clinic and a visiting scientist at Harvard Medical School. “The exceptionally poor results of the US maternal health system demand greater attention to its design. Our study shows that in comparison to other high-income countries, American hospitals may be designed to centre the convenience of clinicians more than the needs of people giving birth."