4.1 Introduction

Clinicians are cautious about prescribing drugs during pregnancy or when a mother is breast feeding due to the possible risks to the fetus and infant. In early pregnancy the risk of teratogenesis is the main concern. The main risks associated with psychotropic drugs in later pregnancy are neonatal toxicity or withdrawal syndrome following delivery and the possibility of a long term impact on the infant's neurodevelopment.¹¹⁹ During breast feeding many drugs taken by the mother are excreted in the milk and ingested by the infant, with consequent concerns about their impact on the infant with regard to both short term toxicity and longer term neurodevelopment.¹²⁰ The level of concern about prescribing during pregnancy and lactation is reflected in the Terms of Marketing Authorisation, with most psychotropic drugs not being licensed for use in pregnancy and lactation. This underlines the need to give very careful consideration to the risks and benefits of prescribing psychotropic medication at this time.

Decisions may have to be made about commencing psychotropic drugs during pregnancy if a woman becomes ill or, more commonly, stopping medication if a woman finds that she is pregnant. As many pregnancies are unplanned, some are exposed inadvertently to psychotropic medication. Advice may then be sought on the need for further investigation and possible therapeutic termination of pregnancy. Studies based on systematic case registers such as the Swedish Medical Birth Registry¹²¹ are contributing to more substantial evidence for such decisions, particularly in relation to teratogenicity.

Scottish case registers to record outcomes for children exposed to psychotropic medication in utero or through breast feeding are required.

Much of the evidence base for risk associated with drug treatments is based on case reports and case series. As new antidepressants are introduced there will continue to be a time-lag in evidence becoming available on which decisions can be made. Evidence is scant for newer agents and for long term developmental risk. It is reasonable to assume that the fetus and newborn are as, if not more, susceptible to the same side effects as adults. The evidence identified demonstrates a relatively low risk with most psychotropic agents, however no treatment is risk-free. Pregnant women and their families have the right to expect that treatments prescribed are clearly indicated and are associated with lowest known risk.

4.2 Drug treatment in the first trimester

4.2.1 ANTIDEPRESSANTS

Evidence indicates no increased risk of major malformation in the newborn or spontaneous abortion following exposure to antidepressants in early pregnancy.^{119,121,122,123,124,125,126} This evidence applies to a variety of tricyclic antidepressants (TCAs) and selective serotonin re-uptake inhibitors (SSRIs);^{119,121,123,124} and more specifically, fluoxetine,^122,125 citalopram,¹²¹ fluvoxamine,¹²⁶ paroxetine,¹²⁶ and sertraline.¹²⁶ Evidence level 2++

The risks of stopping tricyclic or SSRI antidepressant medication should be carefully assessed in relation to the mother's mental state and previous history. There is no indication tostop tricyclic or SSRI antidepressant medication as a matter of routine in early pregnancy.

If a pregnant woman becomes depressed, antidepressant medication should be prescribed with caution and specialist psychiatric advice sought.

Adequate evidence is not available to make recommendations on the use of other antidepressant medications.

4.2.2 MOOD STABILISERS

Lithium

Lithium is regularly used on a maintenance basis in the prevention of relapse of bipolar affective disorder. Such a relapse is more likely to occur following childbirth and when lithium is withdrawn.¹²⁷ Evidence level 2+

Current practice for women with bipolar disorder who plan to or become pregnant ranges from the discontinuation of lithium treatment accompanied by close monitoring or prescription of antipsychotic medication, through to maintenance of lithium throughout pregnancy in cases where the risk of relapse is significant. Evidence is not available to allow comparison of these strategies, but recent studies have allowed a review of the risks associated with lithium treatment.

Early studies of lithium in pregnancy suggested that the risk of major fetal malformations, in particular Ebstein's anomaly, was increased by exposure to lithium in early pregnancy.¹²⁸ Recent evidence, based on prospective studies, suggests that the risk to the fetus of lithium exposure may have been over-estimated and the risk to the mother and child of lithium withdrawal may have been under-estimated.¹²⁷ Evidence level 2+

Where women with severe bipolar disorder are maintained on lithium, consideration should be given to continuing lithium during pregnancy if clinically indicated.

When a woman is maintained on lithium therapy, serum levels should be carefully monitored. Detailed fetal ultrasound scanning (level III) should be offered.

Women with bipolar disorder maintained on lithium should receive specialist supervision.

The risks of lithium to the fetus and the effects of lithium withdrawal on the mother should be discussed before pregnancy.

Other mood stabilisers

The antiepileptic drugs (AEDs) carbamazepine, valproate and, more recently, lamotrigine are also used as mood stabilisers. The evidence from studies of women with epilepsy suggests that exposure to AEDs in early pregnancy increases the risk of congenital malformations and this effect is related to the use of antiepileptic drugs, not the epilepsy.¹²⁹ The relative risk is higher with valproate than carbamazepine and, in particular, with doses of valproate over 1000 mg per day. Evidence level 2+

Several AEDs, including carbamazepine, are folate antagonists. Folic acid supplements are recommended for women on AEDs from preconception to the end of the first trimester.¹³⁰ (See the SIGN guideline Epilepsy in Adults due for publication in late 2002). Evidence level 2+

There is as yet no evidence available on the risks of lamotrigine in early pregnancy.

All women on antiepileptic drugs as mood stabilisers should be prescribed a daily dose of 5 mg folic acid from preconception until the end of the first trimester. D Valproate should be avoided as a mood stabiliser in pregnancy.

The risks of antiepileptic drugs used as mood stabilisers should be discussed with the mother before pregnancy.

4.2.3 OTHER PSYCHOTROPIC MEDICATION

Evidence suggests that exposure to benzodiazepines in early pregnancy increases the risk of major malformations and oral cleft in the fetus.¹³¹ Evidence level 1+

Benzodiazepines should be avoided in the first trimester of pregnancy.

Women inadvertently exposed to benzodiazepines in early pregnancy should be referred for investigation of possible fetal malformation, in particular oral cleft.

Caution should be exercised in the use of any other forms of psychotropic medication in the first trimester of pregnancy.

4.3 Drug treatment beyond the first trimester

The evidence base on the risks of perinatal problems and impaired infant development following exposure to psychotropic medication in pregnancy is limited to single case reports covering a wide variety of types of psychotropic medication, and a limited number of cohort and case-control studies. Perinatal toxic syndromes and withdrawal syndromes following delivery by mothers who received psychotropic medication during pregnancy have been identified, and there are understandable concerns regarding the long term effects of such medication on the neurological development of the infant.¹¹⁹ In particular, newborn infants of women treated with lithium in later pregnancy face potential risks of neonatal toxicity, thyroid and renal dysfunction.¹³²

One cohort study found no evidence of impairment of neurological development at two years after delivery following exposure to antidepressants.¹³³ Evidence level 2+

A case control study found poor neonatal function and withdrawal syndromes in a significant proportion of infants exposed to antipsychotic medication in the last three months of pregnancy.^{119, 134} Evidence level 2++

Neonates exposed to psychotropic medication during pregnancy should be monitored for withdrawal syndromes following delivery.

Psychotropic medication, if considered necessary for the woman's mental state, should be maintained at the minimum effective dose during pregnancy.

Consideration should be given to dose reduction and/or discontinuation two to four weeks before the expected date of delivery, with recommencement after delivery.

4.4 Drug treatment and lactation

Women who develop mental illness following childbirth and need psychotropic medication are likely to be discouraged from breast feeding because of the risks to the infant. However, the risk of breast feeding in this situation may be over-estimated and the advantages under-estimated.¹³⁵ The process of excretion of psychotropic medication is complex, with variation in milk/maternal plasma ratios for different drugs and between foremilk and hindmilk. The level of metabolic maturity of the infant will also influence any effect of drugs taken by the mother. The evidence base is limited due to the small number of breast feeding women who have been exposed to any specific drug and the lack of any systematic approach to monitoring and registering information about the use of psychotropic medication in breast feeding women.¹³⁶

Medications prescribed to breast feeding mothers are best taken as a single dose where possible and should be administered before the baby's longest sleep period.

Breast feeding is best done immediately before administering the dose and should be avoided for one to two hours after any dose of medication (the time of highest plasma concentrations).

4.4.1 TRICYCLIC ANTIDEPRESSANTS (TCAs)

The use of TCAs is diminishing with the introduction of the SSRIs and other novel antidepressants. The evidence base consists mainly of case studies, which confirm that TCAs are excreted in breast milk in higher concentrations in hindmilk than foremilk and the milk/maternal plasma ratio exceeds one. The limited evidence available suggests no short term toxic effects for the infant except in the use of doxepin. ^{120,134,135,137,138,139,140,141} No long term developmental effects for the infant have been demonstrated. Evidence level 2+

There is no clinical indication for women treated with TCAs (other than doxepin) to stop breast feeding, provided the infant is healthy and its progress monitored.

4.4.2 SELECTIVE SEROTONIN RE-UPTAKE INHIBITORS (SSRIs) (update)

SSRIs are being used increasingly in clinical practice. The evidence identified on the use of SSRIs in breast feeding is based on individual case reports and a small case series.

Cumulative evidence on the use of sertraline^{142,143,144,145,146} indicates no significant adverse effects on the breast-fed infant. In one cohort study, 24% of serum samples from infants of nursing mothers taking sertraline had detectable levels of sertraline, particularly where the mother's daily dose was 100 mg or more.¹⁴⁷ No adverse clinical effects have been reported in breast-fed infants of mothers taking paroxetine.^{147,148,149,150} Infant serum levels were undetectable in all studies.^{147,148,149,150} No adverse neurodevelopmental effects were noted in a study of fluoxetine and breast feeding.¹⁵¹ However, fluoxetine and its metabolite nor-fluoxetine have been detected in the serum of a proportion of breast-fed infants whose mothers were taking fluoxetine¹⁵² and nor-fluoxetine has a particularly long metabolic half life.¹⁵³ Paroxetine has the lowest milk/plasma ratio of these three drugs.^146,148,149 Evidence level 2+

There is very limited evidence on citalopram but the milk/maternal plasma ratio is relatively high, as is the calculated infant dose.^154,155,156 There is little evidence on fluvoxamine but it has a low milk/maternal plasma ratio and the calculated dose to the infant is low.^157,158 Evidence level 3

There is no clinical indication for women treated with paroxetine, sertraline or fluoxetine to stop breast feeding, provided the infant is healthy and his or her progress is monitored.

Paroxetine may be the preferred drug because of the low milk/plasma ratio.

4.4.3 MOOD STABILISERS

Evidence indicates that lithium is excreted in breast milk at a level of approximately 40% of maternal serum level. Lithium toxicity has been described in a breast-fed infant and lithium is known to impair thyroid and renal function in adults.^{159, 160} Evidence level 3

In view of the significant risks to the infant of a breast feeding mother taking lithium, mothers should be encouraged to avoid breast feeding. If a decision is made to proceed, close monitoring of the infant, including serum lithium levels, should be provided.

Sodium valproate is excreted in breast milk in low levels and infant serum levels are between one and two per cent of the maternal serum level. No adverse clinical effects have been noted in breast-fed children when mothers are taking sodium valproate.^{159, 161} Evidence level 2-

The evidence on carbamazepine suggests that it is excreted into breast milk in significant quantities and infant carbamazepine levels in serum range from 6% to 65% of maternal serum levels. Evidence level 3

Specialist psychiatric supervision should be provided for women with bipolar affective disorder on mood stabilisers who wish to breast feed.

4.4.4 OTHER PSYCHOTROPIC MEDICATION

Benzodiazepines are excreted in breast milk with a low milk/plasma ratio.^{120, 162} Evidence level 4

New prescriptions for benzodiazepines should be avoided in mothers who are breast feeding.

Note: this recommendation does not cover drug dependence, where breast feeding may be beneficial if the infant has been exposed to benzodiazepines in utero.

All forms of antipsychotic medication are excreted in breast milk but as yet there is no evidence to suggest that breast-fed infants are at risk of toxicity or impaired development.^{119,120,137,162,163} There is little evidence on the new atypical antipsychotic drugs.^{120, 164}

The evidence on other antidepressant drugs including moclobemide,^165,166 venlafaxine,¹⁶⁷ and nefazodone¹⁶⁸ in breast feeding is very limited, but they are all excreted in breast milk. Evidence level 3

If a breast feeding mother is taking psychotropic medication, infant development should be monitored and a careful assessment of the risks and benefits of prescribing at this time should be made.