Big increase in repeat pregnancy rates in HIV-positive women in UK and Ireland

Rates of repeat pregnancies among HIV-positive women in the UK and Ireland have increased substantially since 1997, investigators report in the online edition of the Journal of Acquired Immune Deficiency Syndromes.

In 2009 over a third of all pregnancies involved women who had at least one other pregnancy. Younger age and geographic region of origin were associated with having a subsequent pregnancy.

“A substantial and increasing proportion of pregnancies in diagnosed HIV-infected women are occurring in those who have already received HIV-related care in one or more previous pregnancy,” comment the authors. “The main demographic characteristics independently associated with repeat pregnancies were younger age…and being born in Middle or Western Africa.”

A large proportion of HIV-positive women are of childbearing age. However, mother-to-child transmission can be prevented in most cases with appropriate antiretroviral treatment and care. This low risk of transmission combined with the excellent prognosis provided by modern antiretroviral treatment means that HIV-positive women in resource-rich countries can realistically consider childbearing.

In the UK and Ireland the number of pregnancies in HIV-positive women has increased significantly over the last decade. A significant proportion of these women have experienced at least one other pregnancy while receiving HIV care. Given their often complex medical, obstetric and social needs, the care of this group of women can be complex.

Despite this, little is currently known about the demographics and health status of HIV-positive women who experience repeat pregnancies.

Therefore investigators from the National Study of HIV in Pregnancy and Childhood examined 20 years of data obtained from pregnant HIV-positive women in the UK and Ireland. Data from 1990 and 2009 were included in the study.

The investigators' aims were to characterise the pattern and rate of repeat pregnancies and to establish the demographic and clinical characteristics of HIV-positive women with two or more recorded pregnancies.

A total of 14096 pregnancies were recorded in HIV-positive women during the study period. Just over a quarter (2737; 26%) were repeat pregnancies. This figure included 2117 women who had two pregnancies, 475 with three pregnancies and 145 with four or more pregnancies.

Outcomes were recorded for 13,355 pregnancies. In all, 11,915 (89%) resulted in a live birth, 121 (1%) in a still birth and 10% in either miscarriage or termination.

Both the number and proportion of repeat pregnancies increased significantly. There were 158 recorded pregnancies in 1997, and 32 (20%) were repeat pregnancies. By 2009, the total number of pregnancies had increased to 1465, with 565 (37%) being repeat pregnancies.

Further analysis of the 2009 figures showed that 28% were second pregnancies, 7% were third and 3% were fourth or subsequent pregnancies.

“The increase in repeat pregnancies over the last two decades is likely to reflect a combination of factors including the accumulation of diagnosed HIV-infected women who have already had a pregnancy,” suggest the investigators. “Major improvements in quality of life and AIDS-free survival of people living with HIV, and substantial reductions in the risk of mother-to-child-transmission are also likely to have had an impact.”

Overall, the rate of repeat pregnancies was 6.7 per 100 woman-years.

The median interval between first and second deliveries was 2.7 years, with an interval of 2.3 years between second and third deliveries, with the same interval between third and fourth deliveries.

Analysis of the factors associated with repeat pregnancy was restricted to women who received care after 2000. A total of 11,426 pregnancies in 8661 women were therefore included. Just over a quarter (26%) were repeat pregnancies.

The probability of a repeat pregnancy declined significantly with increasing age (p < 0.001).

Women born in central African countries and West Africa were more likely to experience sequential pregnancies than women born in other regions.

“This pattern is likely to reflect a complex range of cultural, behavioural and migratory factors such as fertility patterns in women’s countries of origin and the demographics of women who migrate from different regions,” write the researchers.

There was no robust evidence that either CD4 cell count or health were associated with repeat pregnancies.

“The number of diagnosed HIV-infected women in the UK and Ireland having more than one pregnancy has increased substantially and is likely to continue to grow,” conclude the authors.

They stress the importance of understanding the characteristics of these repeat pregnancies. “Variations in the probability of repeat pregnancies, according to demographic characteristics, are important considerations when planning the reproductive health services and HIV care for people living with HIV.”