Pre-eclampsia, which affects approximately 1 in every 20 first time pregnancies, could be prevented if high risk pregnant women started taking a dietary supplement containing L-arginine and antioxidant vitamins during their 20th week of pregnancy, researchers from La Universidad Nacional Autonoma de Mexico, Mexico City, reported in the BMJ (British Medical Journal).

Pre-eclampsia, also written preeclampsia is a condition that can develop during pregnancy. There is an abrupt rise in blood pressure (hypertension), large amounts of the protein albumin leaks into the urine (albuminuria), plus there is swelling of the face, hands and feet. It is the most common complication of pregnancy and occurs during the third trimester. It occurs most commonly in first pregnancies. Women who have diabetes or those carrying twins have a higher risk of developing the condition. Some susceptible women develop pre-eclampsia with every pregnancy. The disease tends to run in families, with daughters of mothers who had the condition more likely to develop it themselves.

A pregnant woman with pre-eclampsia needs to stay in bed, sometimes they are prescribed medication. If they do not respond well to treatment the doctor may induce labor or perform a C-section. After the baby is born the problem goes away.

Preeclampsia could be a sign that the placenta is detaching from the uterus. If untreated it can progress to eclampsia, which is a life-threatening condition for both mother and fetus.

The authors explained that pre-eclampsia is believed to be associated with L-arginine deficiency. L-arginine is an amino acid, it helps maintain good blood flow during pregnancy. Many experts believe antioxidant vitamins may provide added protection against pre-eclampsia.

Scientists from Mexico and the USA wanted to determine whether a L-arginine plus antioxidant supplement could help reduce pre-eclampsia rates in high risk women.

Their study took place in a Mexico City hospital involving 667 high risk pregnant women. They were randomly selected to receive:

  • Food bars containing L-arginine plus antioxidant vitamins – 228 patients
  • Food bars containing only vitamins – 222 patients
  • Placebo food bars (no vitamins and no L-arginine) – 222 patients

They started eating the food bars during their 20th week of pregnancy, and continued taking them until they gave birth. Their L-arginine levels plus blood pressure were measured every three to four weeks at the hospital.

The scientist reported the following pre-eclampsia rates in each group:

  • L-arginine group – 12.7%
  • Vitamin only group – 22.5%
  • Placebo group – 30.1%

The study clearly showed that participants in the L-arginine plus antioxidant vitamin group had a considerably lower risk of developing pre-eclampsia compared to those in the placebo group.

The women in the L-arginine plus vitamin group were also found to have a significantly lower risk of having a premature birth compared to those in the placebo group.

The authors concluded:

“This relatively simple and low cost intervention may have value in reducing the risk of pre-eclampsia and associated preterm birth.”

The authors say that a larger study is required to confirm these results, and also to determine whether protection from pre-eclampsia comes from just L-arginine or L-arginine plus vitamins.

“Effect of supplementation during pregnancy with L-arginine and antioxidant vitamins in medical food on pre-eclampsia in high risk population: randomised controlled trial”
Felipe Vadillo-Ortega, Otilia Perichart-Perera, Salvador Espino, Marco Antonio Avila-Vergara, Isabel Ibarra, Roberto Ahued, Myrna Godines, Samuel Parry, George Macones, Jerome F Strauss
BMJ 2011; 342:d2901 doi: 10.1136/bmj.d2901 (Published 19 May 2011)

Written by Christian Nordqvist