Fluoxetine (Prozac) and Pregnancy

Birth Outcomes in Pregnant Women Taking Fluoxetine

Many women are taking the drug fluoxetine (prozac) either when they fall pregnant or while they are trying for pregnancy. There is some research into the outcomes of pregnancies in women who are using this common anti-depressant. There are two concerns with regard to pregnancy and Prozac - firstly whether its use in the first trimester is associated with any risk to the developing fetus - is there an increased risk of congenital abnormalities? Secondly, does it affect the outcome of the pregnancy or the subsequent development of the fetus.

First Trimester Use of Prozac and Congenital Abnormalities

There is no evidence that first trimester use of fluoxetine leads to higher rates of pregnancy loss or increased risk of fetal abnormality [ref's 1-4]. There is consistency among the animal and human studies and significant numbers have now been accrued (about 1000 first trimester exposures in all).

Ongoing Use of Prozac During Pregnancy

In 1996, a study was published that suggested worse outcomes for the babies of women who continued fluoxetine usage during the last trimester of pregnancy [3]. They included 73 exposed infants and found higher rates of early delivery, smaller babies, increased risk of breathing problems and feeding difficulties, and more admissions to the neonatal intensive care unit.

Criticisms of the interpretation of the results of this paper followed [5,6] with particular reference to the fact that the women who continued with fluoxetine probably included those who had more severe depressive illness, and there is already evidence that this alone is a risk factor for worse perinatal outcome. In addition, one of the letters included data on 123 women who continued to use fluoxetine throughout pregnancy, and their outcome was no different to the controls (those who didn't use prozac) of the original study.

There is further reassurance from two other studies which find no increase in problems when fluoxetine is continued into the third trimester. One paper contained 115 exposed infants and looked at differences in early neonatal problems [7], and the other contained 55 exposed infants and examined developmental differences in terms of IQ and language development up to age 7 [8].

Obviously it is important to try and limit the exposure of the developing fetus to drugs, but depressive illness is likely to return if treatment is stopped and uncontrolled depression has its own problems. When fluoxetine is being used for anything more than mild depression, one must weigh up the pros and cons of discontinuing treatment during pregnancy.

Breastfeeding

With regard to breastfeeding and the use of Prozac, there is very little in the published literature to guide. Fluoxetine has a long half-life and it may accumulate in the infant. There is no evidence to reassure that breastfeeding is safe and as one paper puts it, it should be a case-specific, risk-benefit decision. There are other antidepressants, such as the tricyclics (eg. amitriptyline), which do not accumulate in the infant, and with which there is more published experience.

References

1. Pastuszak A, Schick-Boschetto B, Zuber C, et al. Pregnancy outcome following first-trimester exposure to fluoxetine (Prozac). JAMA 1993;269:2246-8
2. Rosa F. Medicaid antidepressant pregnancy exposure outcomes. Reprod Toxicol 1994;8:444
3. Chambers CD, Johnson KA, Dick LM, Felix RJ et al. Birth Outcomes in Pregnant Women Taking Fluoxetine. N Engl J Med 1996;335:1010-5
4. Goldstein DJ; Corbin LA; Sundell KL. Effects of first-trimester fluoxetine exposure on the newborn. Obstet Gynecol 1997 May;89(5 Pt 1):713-8
5. Cohen LS, Rosenbaum JF. Birth Outcomes in Pregnant Women Taking Fluoxetine. N Engl J Med 1996; 336: 872-3 (Letters)
6. Goldstein DJ, Sundell KL, Corbin LA. Birth Outcomes in Pregnant Women Taking Fluoxetine. N Engl J Med 1996; 336: 872-3 (Letters)
7. Goldstein DJ. Effects of third trimester fluoxetine exposure on the newborn. Journal of Clinical Psychopharmacology. 1995; 15: 417-20
8. Nulman I, Rovet J, Stewart DE et al. Neurodevelopment of Children Exposed in Utero to Antidepressant Drugs. N Engl J Med 1997;336:258-62