Deficits in plasma oxytocin responses and increased negative affect, stress, and blood pressure in mothers with cocaine exposure during pregnancy

Abstract

In animals, oxytocin enhances maternal behavior and lowers blood pressure (BP) and negative affect, while parturitional cocaine disrupts oxytocin activity and increases maternal neglect and aggression. Thus, we compared oxytocin, BP, maternal behavior, and affect in mothers of infants who used cocaine (cocaine, n = 10) or did not (no drug, n = 25) during pregnancy. Laboratory BP and circulating oxytocin, catecholamines, and cortisol were examined before and during a speech stressor on 2 days, with vs. without prestress baby holding. Ambulatory monitoring assessed BP, urinary norepinephrine, and cortisol for 24 h at home. The cocaine group had lower oxytocin levels, greater hostility and depressed mood, less support from others and mastery over life events, higher BP during all events of testing without the baby, and higher ambulatory BP and urinary norepinephrine at home, while cortisol and epinephrine responses were blunted. Although they tended to hold their babies less often at home, baby holding in the laboratory led to decreased BP in cocaine mothers who then did not differ from no-drug mothers in BP or observed affect.

Fig. 1

Differences in laboratory systolic blood pressure (SBP) levels during baseline, speech preparation, active speech, and recovery periods on the baby contact vs. the no baby test days for the cocaine-exposed vs. no-drug groups. Cocaine group SBP>no-drug group SBP for baseline, preparation, and recovery on the no baby day, Ps < .075, .034, and .039, respectively, but during speech on both days and during all events on the baby day, all Ps = NS; effect sizes for group differences on the no baby vs. baby days are 0.10 vs. 0.02 for baseline, 0.14 vs. 0.02 for preparation, 0 vs. 0.01 for speech, and 0.14 vs. 0.08 for recovery.

Fig. 2

Differences in laboratory diastolic blood pressure (DBP) levels during baseline, speech preparation, active speech, and recovery periods on the baby contact vs. the no baby test days for the cocaine-exposed vs. no-drug groups. Cocaine group DBP>no-drug group DBP for baseline, preparation, and recovery on the no baby day, Ps < .026, .007, and .066, respectively, but during speech on both days and during all events on the baby day, all Ps = NS; effect sizes for group differences on the no baby vs. baby days are 0.16 vs. 0 for baseline, 0.24 vs. 0.01 for preparation, 0 vs. 0.01 for speech, and 0.14 vs. 0 for recovery. In addition, for the cocaine group only, DBP levels on the no baby day are higher than on the baby day, P < .05 for preparation and recovery, P < .07 for baseline and speech.

Fig. 3

Plasma oxytocin levels during single combined baseline and during speech on both the baby contact and no baby test days are lower for the cocaine-exposed vs. no-drug groups.

Fig. 4

Mean ambulatory levels of SBP during sleep, postfeeding, and all other waking activities are higher for the cocaine vs. the no-drug group (breast-feeding + bottle-feeding mothers combined), P < .005.

Fig. 5

Mean ambulatory levels of DBP during sleep, postfeeding, and all other waking activities are higher for the cocaine vs. the no-drug group (breast-feeding + bottle-feeding mothers combined), P < .05.