Miscarriage increased the risk of developing gestational diabetes in the next pregnancy

A systematic review and meta-analysis by Australian researchers found that a previous miscarriage increased the risk of developing gestational diabetes in subsequent pregnancies. In addition, women with habitual non-pregnancy (two or more miscarriages in the history) had an increased risk of subsequent pre-eclampsia. The results of the analysis are published in the journal eClinicalMedicine.

Spontaneous abortion, or miscarriage, occurs in about 15 to 25 percent of all pregnancies. It is estimated that the number of miscarriages reaches 23 million each year worldwide. In addition, one to two percent of women experience recurrent pregnancy loss - habitual non-pregnancy, in which two or three or more consecutive pregnancy losses occur. Yet little is known about the impact of previous miscarriages on complications of subsequent pregnancies in the context of their effect on cardiovascular risk.

Women who have had a miscarriage are known to be at greater risk of subsequent pregnancy complications such as placental abruption, fetal growth retardation, preterm labor, and stillbirth. All of these are associated with a subsequent increased risk of cardiovascular disease. Recently, there has been increased interest in the potential impact of early pregnancy loss on the subsequent development of diabetes and hypertensive disorders in women. However, there is limited evidence to support an association between early pregnancy loss and subsequent risk of developing diabetes mellitus or hypertensive disorders.

Australian researchers led by Jennifer Dunne of Curtin University attempted to address this by conducting a systematic review and meta-analysis of studies on the topic. Their work included 52 research articles with a total sample of 4132895 women from 22 countries. 35 articles were eligible for meta-analysis.

Pooled evaluations of 19 studies showed that women who had a miscarriage had a 44 percent higher risk of developing gestational diabetes in subsequent pregnancies. However, women who underwent induced abortion did not have an increased risk of developing gestational diabetes in subsequent pregnancies. A similar lack of significant effect on the development of gestational diabetes scientists found in women with habitual non-pregnancy. Notably, none of the forms of pregnancy termination increased the risk of developing type 2 diabetes.

A meta-analysis of 12 studies showed that spontaneous miscarriage had no effect on the risk of developing pre-eclampsia in subsequent pregnancies. A similar result was found when the effect of induced abortion was studied. However, an unintended pregnancy increased the risk of pre-eclampsia by 37 percent on average. In addition, women who had a miscarriage had an increased chance of developing gestational hypertension in subsequent pregnancies.

The results of this study suggest that early pregnancy loss may have long-term health consequences in subsequent pregnancies. These findings will be relevant for assessing the risk of pregnancy complications in women with a known reproductive history, and possibly for developing prevention of pregnancy complications.