Why does metabolism increase during pregnancy?

Pregnancy Metabolism Your body is requiring more nutrients to feed both you and your baby. Your uterus will enlarge and the amniotic sac will be filled with amniotic fluid. The amniotic fluid is there to protect your baby from any bumps or falls.

How does phenytoin affect pregnancy?

Phenytoin is a medication used to treat epilepsy (seizure disorder). If phenytoin is taken by the mother in the first trimester, there is approximately a 5 to 10 percent chance that the baby could be born with a combination of birth defects known as the Fetal Hydantoin Syndrome.

Do you metabolize drugs faster when pregnant?

Results from clinical pharmacokinetic studies indicate clearances of drugs metabolized by selected drug metabolizing enzymes (e.g., CYP2D6 and CYP3A4) increased, whereas those of drugs metabolized by other enzymes (e.g., CYP1A2) decreased during pregnancy as compared to non-pregnant women [7, 9, 22].

How does pregnancy affect drug distribution?

Drug absorption is affected by slower gastric emptying and slower bowel and colonic transit time. The increased plasma volume, change in protein binding, and lower ratio of lean muscle to adipose tissue during pregnancy may result in a greater volume of drug distribution for lipophilic drugs.

Does pregnancy affect metabolism?

Metabolic rates increase substantially by just 15 weeks’ gestation and peak in the third trimester during the greatest growth phase. This increased metabolic rate may put pregnant women at a higher risk of hypoglycemia, or low blood sugar.

How does metabolism change in pregnancy?

Maternal metabolism changes substantially during pregnancy. Early gestation can be viewed as an anabolic state in the mother with an increase in maternal fat stores and small increases in insulin sensitivity.

What pregnancy category is phenytoin?

US FDA pregnancy category D: There is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience or studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.

Can phenytoin cause neural tube defects?

However, the pattern of malformations varies. Heart defects seem to dominate among children exposed to barbiturates, and to some extent phenytoin and carbamazepine, whereas neural tube defects and hypospadia are more common among offspring of mothers taking valproate during pregnancy.

Should all medicines be avoided during pregnancy?

Doctors usually tell women to avoid medicines during pregnancy, if possible, especially during the first 3 months. That is when a baby’s organs form. But sometimes you have to take medicine to treat a health problem, such as high blood pressure or asthma.

Does peripheral resistance increase in pregnancy?

In the first trimester, there is a substantial decrease in peripheral vascular resistance, which decreases to a nadir during the middle of the second trimester with a subsequent plateau or slight increase for the remainder of the pregnancy3 (Figure 1).

Why during pregnancy drug distribution is more?

In general, small-molecular-weight and lipophilic drugs readily cross the placenta. The fetus and the amniotic fluid can act as additional compartments, leading to increased drug accumulation and an apparent increase in volume of distribution of certain drugs.

When does your metabolism increase in pregnancy?

The basal metabolic rate The rate begins to rise during the third month of pregnancy and may double the normal rate (+10 percent) by the time of delivery.

How does pregnancy affect the absorption of phenytoin?

Pregnancy alters the metabolism of phenytoin and all AEDs, ultimately leading to lower serum drug levels. Delayed gastric emptying in pregnancy decreases drug absorption, and increased renal and hepatic activity speed metabolism and excretion.

Is it safe to take phenytoin during pregnancy?

The American College of Obstetricians and Gynecologists recommends 4 mg of folate per day for women taking phenytoin (Dilantin) during pregnancy. [ 9] Serum phenytoin levels should be checked before beginning folate supplementation. [ 8] Pregnancy alters the metabolism of phenytoin and all AEDs, ultimately leading to lower serum drug levels.

How is phenytoin used to treat fetal hydantoin syndrome?

The specific amount of phenytoin ingestion required to cause the disorder has not been determined. Phenytoin is often given with other anti-seizure drugs and other (adjunct) medications that may influence development of the disorder. Fetal hydantoin syndrome may be caused by a combination of specific genetic and environmental factors.

Which is the major metabolite of phenytoin?

The metabolism of phenytoin to the major metabolite, 5-(p-hydroxyphenyl)-5-(phenylhydantoin, is saturable, giving rise to a non linear dose-serum concentration relationship.