Human chorionic gonadotrophin (hCG) for preventing miscarriage

Recurrent miscarriage (RM) is defined as the loss of three or more consecutive pregnancies. Further research is required to understand the causes of RM, which remain unknown for many couples. Human chorionic gonadotrophin (hCG) is vital for maintaining the corpus luteum, but may have additional roles during implantation which support its use as a therapeutic agent for RM.

To determine the efficacy of hCG in preventing further miscarriage in women with a history of unexplained RM.

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 September 2012) and reference lists of retrieved studies.

Randomised controlled trials investigating the efficacy of hCG versus placebo or no treatment in preventing RM. Quasi-randomised trials are included. Cluster-randomised trials and trials with a cross-over design are excluded.

Two review authors independently assessed trials for inclusion and assessed the methodological quality of each study. Date were extracted by two review authors and checked for accuracy.

We included five studies (involving 596 women). Meta-analysis suggested a statistically significant reduction in miscarriage rate using hCG.The number of women needed to treat to prevent subsequent pregnancy loss was seven. However, when two studies of weaker methodological quality were removed, there was no longer a statistically significant benefit (risk ratio 0.74; 95% confidence interval 0.44 to 1.23). There were no documented adverse effects of using hCG.

The evidence supporting hCG supplementation to prevent RM remains equivocal. A well-designed randomised controlled trial of adequate power and methodological quality is required to determine whether hCG is beneficial in RM.