Low-molecular-weight heparin (LMWH) does not increase ongoing pregnancy or live-birth rates in women with a viable pregnancy and unexplained recurrent pregnancy loss (RPL), according to a new study.
“Our data show that LMWH prescribed to women with unexplained RPL and a viable pregnancy does not increase live-birth rates. Moreover, our data show that any effect LMWH may have is minimal,” the researchers write. “Given the burden of daily injection, we do not recommend its use in such women for the purpose of reducing miscarriage rates.”
Ekkehard Schleussner, MD, PhD, from Friedrich Schiller University Hospital, Jena, Germany, and colleagues report their findings in an article published in the May 5 issue of the Annals of Internal Medicine.
LMWH can increase live-birth rates in women with recurrent pregnancy loss caused by thrombophilic disorders, but it is unclear whether it can also help women without thrombophilic disorders who have unexplained recurrent pregnancy loss.
The researchers conducted a randomized controlled, open-label multicenter trial from 2006 to 2013. They included 449 women who had experienced at least two consecutive early miscarriages (<12 weeks’ gestation) or one late miscarriage (≥12 weeks’ gestation) and had a viable singleton pregnancy confirmed by ultrasonography during 5 to 8 weeks’ gestation.
The researchers randomly assigned the women to receive either multivitamin pills or multivitamins plus a daily injection of dalteparin-sodium 5000 IU for up to 24 weeks’ gestation.
The study’s primary outcome was ongoing pregnancy at 24 weeks’ gestation. Secondary outcomes included late pregnancy complications and the live-birth rate.
The important distinction here is that it is still recommended for certain patients who have heredity blood clotting abnormalities called thrombophilias. These abnormalities can be detected in the blood tests usually performed when a couple has experienced a number of miscarriages.
Most miscarriages are caused by chromosomal abnormalities in the pregnancy and if no other reason is found, preimplantation genetic screening (PGS) in an IVF cycle is helpful in selecting chromosomally normal embryos to transfer and help avoid another loss.