Researchers in the department of global public health and primary care at the University of Bergen in Norway recently investigated pregnancy term complications. Term complications and premature births are not uncommon occurrences. In many cases, when a women experiences term complication in her first pregnancy, medical professionals pay close attention to her subsequent pregnancies due to the possibility of complications occurring again. In some cases, a subsequent preterm birth occurs. Is there a correlation you ask? That is what researchers wanted to discover. The researchers at the University of Bergen were eager to determine if there is a correlation between term complications and subsequent preterm births.

This research experiment consisted of obtaining data from birth registries and analyzing the data in order to determine possible correlations. Researchers collected data for over 300,000 women who gave birth to a second child between 1999 and 2015. The data included variables such as demographics, medical and reproductive history, lifestyle, complications during pregnancy and delivery, and fetal outcomes. The researchers chose to focus on women whom had a term first birth, however, they experienced term complications. Complications can include pre-eclampsia (high blood pressure), placental abruption (placenta separates from the inner wall of the uterus too early), stillbirth, neonatal death, and small for gestational age (how far along the pregnancy is). Upon identifying the women that fit the criteria, researchers analyzed the second pregnancy of each women. In addition, they acknowledged additional variables that could have served as explanatory variables.

I am sure that you are dying to know what the researchers discovered. I suppose I won’t make you wait any longer. Women with pre-eclampsia in their first pregnancy have a 6.1% risk of subsequent preterm births. This happens to be the lowest risk. Women with an infant that was small for gestational age in their first pregnancy have 6.7% risk of subsequent preterm births. Women with placental abruption in their first pregnancy have a 7.3% risk of subsequent preterm births. Unfortunately, we are still not even at the highest risk group and 7.3% is still very high. Women that experience a neonatal death in their first pregnancy have a 10% risk of subsequent preterm births. Finally, women that experience a stillbirth in their first pregnancy have a 13.1% risk of subsequent preterm births. If you are alarmed by that number, I do not blame you, but I may have some information that will ease your mind.

There are risks associated with having term complications during the first pregnancy, however, there is not a strong correlation. The majority of individuals with term complications do not experience a preterm birth in their second pregnancy. In addition, there are other variables that impacted the relative risks identified in this experiment. Some explanatory variables may include age, demographics, and underlying medical history of the mother. What I am trying to say is, do not panic quite yet. Term complications may play a role in subsequent preterm births, but it is not the only contributing factor.

Kvalvik, L.G., Wilcox, A.J., Skjaerven, R., Ostbye, T., & Harmon, Q.E. 2020. Term complications and subsequent risk of preterm birth: registry based study. BMJ 369: 1-9.