ADELAIDE, SOUTH AUSTRALIA: A pathfinding Chinese study has found that women who have suffered two or more miscarriages have a significantly higher risk of obstetric and perinatal complications in subsequent pregnancies.

It has cast light on a possible altered micro-environment at the maternal-foetal interface in women with recurrent miscarriage that may affect foetal growth and development.

The retrospective research project involved a large cohort of women in Hong Kong who had experienced recurrent miscarriages finding that in subsequent pregnancies they showed an increased prevalence of hypertension, and that their babies were often small for gestational age and delivered pre-term.

It also revealed a significant difference in the incidence of perinatal death compared to pregnancy outcomes in women who had no previous history of miscarriage.

The disturbing results of the joint study by the Shenzhen Baoan Women’s and Children’s Hospital and the Chinese University of Hong Kong were outlined today at the 2023 Congress of the Asia Pacific Initiative on Reproduction (ASPIRE) in South Australia.

Dr Xiaoyan Chen said the researchers compared obstetric data from 3,112 women who had experienced recurrent miscarriages with 108,012 women who had no record of pregnancy loss.

Of the 3112 women, 22.4 per cent had suffered primary recurrent pregnancy loss – meaning they had never given birth to a live infant – and 77.6 per cent had secondary miscarriage, meaning they had previously given birth.

“Women in the study cohort and control group were aged from under 20 to over 40 years and we looked at numerous factors including marital status, natural or assisted conception, infant gender, size of babies for gestational age and mode of delivery,” Dr Chen explained.

“Of those with a history of recurrent miscarriage we also investigated data including congenital abnormalities and perinatal death.”

Previous studies on recurrent pregnancy loss, which affects up to three per cent of women globally, have only occurred among Caucasian populations in the United States and Europe. The research presented at the ASPIRE meeting today was the first among Chinese women.

Dr Chen said the recurrent miscarriage in the 3,112 women were from:
• unexplained causes (1,276);
• immune system disorders (389);
• uterine abnormalities (209);
• endocrine anomalies (302);
• genetic factors (350); and
• multiple causes (586).

She said more research was required to understand the unexplained causes of recurrent miscarriage.

“However, our study clearly shows that women with a history of two of more miscarriages have an increased risk of obstetric and perinatal complications in subsequent pregnancies,” Dr Chen said.

“These women should be offered specialist obstetric care from the start of pregnancy with an emphasis on strategies to manage the increased risk of pre-term birth, small for gestational age and perinatal death,” Dr Chen added.

The ASPIRE Congress at the Adelaide Convention Centre has brought together about 1,400 specialists in assisted reproduction including leaders in the field from the Asia Pacific region.

ASPIRE 2023 Congress Media Release, 10 September 2023