Many practitioners consider
low-molecular-weight heparin (
LMWH) an alternative to
unfractionated heparin, although there are limited safety data regarding maternal and fetal outcomes in patients using an
LMWH during pregnancy. A retrospective chart review was performed on 72 patients with
thrombophilia exposed to the
LMWH,
enoxaparin, during pregnancy. Eighty-five pregnancies resulted in 93 of 99 potential live births. Eleven of 12 twin pregnancies and one triplet pregnancy were successful. One preterm live birth infant of 33 weeks' gestation did not survive. Three patients with
thrombophilia spontaneously aborted. A patient receiving
injectable fertility treatment had spontaneously aborted one twin at 5 weeks' gestation. One patient terminated the pregnancy after discovering the presence of
Down's syndrome. The mean maximum dose required to achieve a therapeutic anti-Xa level of 0.2-0.4 IU/mL at 5 to 6 hours following administration, was 38.1 mg every 12 hours (median 35 mg, range 30-75 mg every 12 hours). The mean anti-Xa level was 0.28 IU/mL (median 0.3, range 0.05-0.8 IU/mL). A total of nine patients experienced
bleeding events, two requiring discontinuation of
enoxaparin for the remainder of the pregnancy. Two patients experienced
injection site reactions requiring discontinuation of
enoxaparin. Three patients developed
preeclampsia, two placenta abruptio, and one
placenta previa. No thromboembolic complications or
osteoporotic fractures had occurred.
Enoxaparin was safe and effective for preventing
thromboembolism and adverse obstetrical complications in our patients, including 12 of 13 multiple gestation pregnancies.