This drug should be used only if the potential benefit justifies the risk to the fetus, taking into account the risks of untreated Bipolar I depression or treatment-resistant depression.

US FDA pregnancy category: C

Comments:
-A pregnancy exposure registry is available.
-Newborns should be monitored if the maternal use of this drug continues into the later stages of pregnancy, particularly, the third trimester.
-Abrupt discontinuation should be avoided during pregnancy.

Animal studies have failed to reveal evidence of teratogenicity. Decreased fetal weight and retarded skeletal ossification was observed at high doses (9 and 2 times the maximum recommended human dose for olanzapine and fluoxetine, respectively) that were also maternotoxic. There are no controlled data in human pregnancy.

Results of a number of epidemiological studies assessing the risk of fluoxetine exposure in early pregnancy have been inconsistent and not provided conclusive evidence of an increased risk of congenital malformations. Some epidemiological studies suggest an increased risk of cardiovascular malformations; however, the mechanism is unknown. Overall, data suggest that the risk of having an infant with a cardiovascular defect following maternal fluoxetine exposure is approximately 2 in 100 compared with 1 in 100 for the general population.

Neonates exposed to SSRIs and SNRIs late in the third trimester have uncommonly reported clinical findings including respiratory distress, cyanosis, apnea, seizures, temperature instability, feeding difficulty, vomiting, hypoglycemia, hypotonia, hypertonia, hyperreflexia, tremor, jitteriness, irritability, and constant crying. These effects have mostly occurred either at birth or within a few days of birth. These features are consistent with either a direct toxic effect of SSRIs and SNRIs, or possibly a drug discontinuation syndrome; in some cases, the clinical picture is consistent with serotonin syndrome.

Epidemiological data have suggested that the use of SSRIs, particularly in late pregnancy, may increase the risk of persistent pulmonary hypertension in the newborn. Data are not available for SNRIs.

The results of a cohort study indicated that 30% of neonates who had prolonged exposure to SSRIs in utero experienced symptoms, in a dose-response manner, of a neonatal abstinence syndrome (e.g., tremor, gastrointestinal or sleep disturbances, hypertonicity, high-pitched cry) after birth. The authors suggest that infants exposed to SSRIs should be closely monitored for a minimum of 48 hours after birth.

A prospective study of 128 pregnant women exposed to a mean daily dose of 25.8 mg of fluoxetine during the first trimester reported no increase in the frequency of major malformations compared to two groups of control patients. (One control group received tricyclic antidepressants. The other control group received non-teratogens.) However, women exposed to fluoxetine and tricyclic antidepressants did demonstrate an increased frequency of miscarriage (13.5% and 12.2% compared to 6.8% in women exposed to non-teratogens.)

A prospective study compared rates of neonatal complications from 112 pregnant women taking fluoxetine and the 115 infants they delivered to data from a pregnancy registry. The study concluded it was unlikely that maternal fluoxetine use during the third trimester results in significant postnatal complications.

A prospective study compared the outcome of 228 pregnant women taking fluoxetine to 254 pregnant control women. The rates of spontaneous pregnancy loss were 10.5% and 9.1%, respectively. The rates of major structural abnormalities were 5.5% and 4%. The incidence of three or more minor anomalies was significantly higher in exposed infants (15.5% versus 6.5%). Infants exposed during the third trimester had high rates of premature delivery, admission to special care nurseries, and poor neonatal adaptation (including respiratory difficulty, cyanosis on feeding and jitteriness). Infants exposed late in gestation had shorter birth lengths and lower birth weights.

The above study has been criticized for the absence of a relevant control group. Higher rates of perinatal complications, including lower birth weight, neonatal distress and prematurity, have been described in the offspring of mothers with mood and anxiety disorders who did not take any psychotropic drug during pregnancy. In addition, the women who continued to take fluoxetine into the third trimester most likely had more severe psychiatric illnesses.

Neonates exposed to antipsychotic drugs during the third trimester of pregnancy are at risk for extrapyramidal and/or withdrawal symptoms following delivery. Reports of agitation, hypertonia, tremor, somnolence, respiratory distress, and feeding disorder have varied in severity. Some cases were self-limiting; however, in other cases neonates required intensive care and prolonged hospitalization.

Animal toxicology studies reported decreased ovary weight, corpora luteal depletion, uterine atrophy in females, and reduced epididymal sperm, testicular and prostate weights in males in high-dose combinations. Data from other animal studies has shown that fluoxetine may affect sperm quality. Human case reports from some SSRIs have shown this effect to be reversible. As yet, the impact of this on human fertility has not been observed.

To monitor maternal-fetal outcomes of pregnant women exposed to antidepressant and/or antipsychotic therapy, a National Pregnancy Registry for Psychiatric Medications has been established. Healthcare providers are encouraged to prospectively register patients. For additional information: https://womensmentalhealth.org/clinical-and-research-programs/pregnancyregistry/.

US FDA pregnancy category C: Animal reproduction studies have shown an adverse effect on the fetus and there are not adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.

See references

The average amount of drug in breastmilk is higher with fluoxetine than with most other SSRIs, and the long-acting active metabolite, norfluoxetine, is detectable in the serum of most breastfed infants during the first 2 months postpartum and in a few thereafter. No adverse effects on development have been reported in a few infants followed for up to one year.

It has been suggested that fluoxetine therapy may be continued during breastfeeding if it was used during pregnancy or if other antidepressants were ineffective. Alternatively, medicines with a lower excretion into breastmilk may be preferred, particularly when nursing a newborn or preterm infant.

An infant breastfed by a mother receiving oral fluoxetine therapy developed crying, sleep disturbance, watery stools, and vomiting. The infants' plasma drug levels of fluoxetine and norfluoxetine on the second day of feeding were 340 ng/mL and 208 ng/mL, respectively.

A report of ten women nursing eleven infants found that less than 10% of the dose of fluoxetine (per kg of body weight) was delivered to the nursing infant during chronic maternal therapy. Other reports from two lactating women taking fluoxetine have described milk fluoxetine and norfluoxetine concentrations to be about one-fifth to one-quarter of the serum concentrations. No adverse effects were reported in these nursing infants.

A study involving lactating, healthy women reported a mean infant dose at steady-state of approximately 1.8% of the maternal olanzapine dose.

Very limited long-term follow-up of infants exposed to olanzapine indicates that infants generally developed normal; however, combinations of antipsychotic agents may negatively affect development. Two cases of exposure to olanzapine during lactation have been reported. One infant experienced adverse effects which continued after olanzapine was discontinued, suggesting an alternate cause. No problems were reported in the other infant.

Spontaneous reports, clinical trials, and published reports of adverse effects in breastfed infants exposed to olanzapine were collated by the manufacturer. They indicated that, of the 102 breastfed infants exposed to olanzapine via breastmilk, 15.6% reportedly experienced side effects. The primary side effects reported included somnolence, irritability, tremor, and insomnia.

A decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.

Excreted into human milk: Yes (fluoxetine, olanzapine)

Comments:
-Breastfed infants should be monitored for side effects such as colic, fussiness, sedation, and adequate weight gain.
-Monitoring for drowsiness and developmental milestones is also recommended, particularly if other antipsychotics are used concomitantly.
-Mothers taking an SSRI during pregnancy and postpartum may have difficulty breastfeeding and may require additional breastfeeding support.

See references