Infants Of Substance-abusing Mothers Research Articles

Improving Pathways to Assessment and Care for Infants of Substance Abusing Mothers: Are We Getting It Right?

There is documented correlation between parental substance abuse, child maltreatment, and poor outcomes. In two health districts in Sydney, Australia (Site A and B), specialised clinics were established to provide comprehensive assessments for infants of substance abusing mothers (ISAM). We aimed to determine whether there was a difference in outcomes between infants who attended clinic versus those who did not; and to identify differences in the pathways to care between sites. We analysed child protection reports and available health markers of all ISAM referrals in 2011. We held stakeholder meetings with services involved with ISAM in both sites; to describe service components; strengths and weaknesses of pathways. Fifty-five per cent (11/20) attended clinic in Site A; 80% (25/31) in Site B. Three-quarters of ISAM had at least one referral to child welfare; child protection service involvement was more common in those who attended. Immunisation status was lower than the national Australian average; approximately half were seen by community nursing services. Gaps in services, lack of database, and differences in pathways between sites were identified. Attending clinics correlates with child protection service involvement and may afford health protection. Transparent communication, service integration, and shared learning can improve outcomes for this vulnerable group.

Sleep Architecture in Infants of Substance-Abusing Mothers.

This longitudinal, year-long study compared sleep-wake state organization in two groups of infants-infants whose mothers abused substances during their pregnancies and nonexposed, typically developing, age-matched comparison infants-to determine whether differences in sleep-wake state organization existed between the two groups. Seventeen infants of mothers who were participating in a parent-infant residential treatment program for substance abuse were enrolled. Their sleep-wake state organization over the first year of life was compared to that of 17 age-matched comparison infants. The intent was to follow each infant on five occasions over the first year of life using established methods of time-lapse videosomnography to record sleep-wake state organization; however, attrition in the substance-abusing group was problematic. Some sleep-wake variables (i.e., Active Sleep%, Quiet Sleep%, Awake%, number of nighttime awakenings) were similar for both groups of infants at comparable ages across the first year. Total sleep time and the longest sustained sleep period (sleep continuity variables) differed significantly at some of the ages measured. Although overall sleep architecture appears highly resilient and well organized, some indications of sleep fragmentation and shortened nighttime sleep periods were observed in the substance-exposed infants. More research is needed to explain why sleep-continuity variables and not sleep-state proportion variables differed between the two groups.

Serum cortisol levels in very low birth weight infants of substance-abusing mothers.

Recently, hypoadrenalism was described in extremely low birth weight infants. We have been measuring serum cortisol levels in very low birth weight (VLBW) infants to assess their adrenal function. It was noticed that infants of substance-abusing mothers (ISAM) had unusually high serum cortisol levels. To our knowledge, there are no data regarding serum cortisol levels in VLBW ISAM. The objective of our study was to determine if serum cortisol levels of VLBW ISAM are different from serum cortisol levels in VLBW infants without a history of maternal substance abuse. We reviewed medical records of infants with birth weight between 400 and 1300 gm who were born between July 1994 and June 1995. Seven ISAM who had serum cortisol levels drawn before 48 hours of life were identified. Seven infants matched for gestational age, antenatal steroid exposure, and birth weight served as control infants. Clinical characteristics, serum cortisol levels, and clinical outcome were compared between the two groups. Serum cortisol levels of all infants were measured by radioimmunoassay. The mean birth weight of the ISAM group was 834 gm (range 480 to 1175 gm), and the mean gestational age was 27.4 weeks. The mean birth weight of the control group was 921 gm (range 525 to 1230 gm) with a mean gestational age of 27.8 weeks. The mean serum cortisol level of the ISAM group was 65.3 micrograms/dl (range 11.9 to 144 micrograms/dl); it was significantly higher than that of the control group (mean cortisol level of 20.5 micrograms/dl; range 4.9 to 62.7 micrograms/dl) (p = 0.01, two-tailed). Our data suggest that maternal substance abuse significantly increases serum cortisol levels in VLBW infants. Studies in larger scale are needed to confirm our findings and to correlate cortisol levels in this group of patients with clinical outcome.

Decreased Carbon Dioxide Sensitivity in Infants of Substance-Abusing Mothers

To determine whether there is a demonstrable abnormality in control of breathing in infants of substance-abusing mothers during the first few days of life. We enrolled 12 drug-free control infants and 12 infants of substance abusing mothers (ISAMs). These infants experienced otherwise uncomplicated term pregnancies and deliveries. The infants were assigned to a group based on the results of maternal histories and maternal and infant urine toxicology screens. Studies were performed during quiet sleep during the first few days of life. We measured heart rate, oxygen saturations via a pulse oximeter, end-tidal carbon dioxide (ET-CO2) level, respiratory rate, tidal volume, and airflow. The chemoreceptor response was assessed by measuring minute ventilation and the ET-CO2 level after 5 minutes of breathing either room air or 4% carbon dioxide. The gestational ages by obstetrical dating and examination of the infants were not different, although birth weights and birth lengths were lower in the group of ISAMs. Other demographic data were not different, and there were no differences in the infants' median ages at the time of study or in maternal use of tobacco and alcohol. The two groups had comparable baseline (room air) ET-CO2 levels, respiratory rates, tidal volumes, and minute ventilation. When compared with the group of ISAMs, the drug-free group had markedly increased tidal volume and minute ventilation on exposure to 4% carbon dioxide. These increases accounted for the difference in sensitivity to carbon dioxide, calculated as the change in minute ventilation per unit change in ET-CO2 (milliliters per kg/min per mm Hg). The sensitivity to carbon dioxide of control infants was 48.66 +/- 7.14 (mean +/- SE), whereas that of ISAMs was 16.28 +/- 3.14. These data suggest that ISAMs are relatively insensitive to challenge by carbon dioxide during the first few days of life. We speculate that this reflects an impairment of the chemoreceptor response.

Respiratory abnormalities in infants of substance-abusing mothers: role of prematurity.

It is a current hypothesis that maternal history of drug addiction during pregnancy and detection of drugs in the urine of the newborn are associated with increased incidence of apnea. To test this hypothesis, we reviewed polygraphic studies of respiration in two groups of infants who had been exposed in utero to cocaine (and other drugs). The first group was composed of 20 term infants (39.1 +/- 0.8 weeks gestation), and premature infants (35.4 +/- 0.8 weeks gestation). None of the infants were on methylxanthines. These infants were matched with 15 term and 15 preterm infants of similar gestational age. Variables studied were: heart rate, respiration, chest impedance pneumography, nasal airflow and oxygen saturation (pulse oximetry). Apnea indices for central and obstructive events of short and long duration as well as periodic breathing and oxygen saturation were obtained. Term drug-exposed infants had less central apnea and a higher rate of periodic breathing compared to term controls, whereas drug-exposed premature infants had more obstructive apnea and less periodic breathing compared to premature controls. These observed differences within groups were subtle and clinically insignificant. Other parameters studied were not different. When term and preterm infants were compared, preterm infants had significantly higher central apnea, obstructive apnea and periodic breathing rates. These differences appeared to be related to gestational age differences, not to drug exposure. There was no evidence that exposure to cocaine and other drugs actually inhibited respiration.

Prenatal Substance Abuse

It has been reported that ISAM have an increased risk of SIDS and abnormalities of cardiorespiratory physiology. Abnormalities of cardiorespiratory control may account for the increased SIDS risk in some ISAM, and home monitoring is often used for ISAM with clinical apneic episodes. However, it is possible that the increased SIDS risk factors concentrated in this population. The increased SIDS risk SIDS risk factors concentrated in this population. The increased SIDS risk demonstrated in ISAM does not necessarily indicate that drug exposure during gestation in itself causes SIDS. Thus home monitoring is not indicated for ISAM who do not have apnea or other clinical evidence of a respiratory control abnormality.

Responses to hypoxia and hypercapnia in infants of substance-abusing mothers

Because infants of substance-abusing mothers (ISAM) have an increased risk of sudden infant death syndrome and have abnormal sleeping ventilatory patterns, we studied the effects of mild hypoxia during quiet sleep on ventilatory pattern, heart rate, and arousal in 23 healthy ISAM (mean +/- SEM: 9.0 +/- 0.49 weeks of age) and 15 healthy, similarly aged, control infants. Hypercapnic challenges were performed in six ISAM and eight control subjects. Hypoxic arousal responses were elicited by rapidly decreasing inspired oxygen tension to 80 mm Hg for 3 minutes or until arousal occurred. Failure to arouse to hypoxia occurred in the majority of infants in both groups. All infants had a fall in end-tidal carbon dioxide tension during hypoxia, suggesting that each had a hypoxic ventilatory response. However, the fall in end-tidal carbon dioxide tension was significantly less in the ISAM (mean +/- SEM: -4.0 +/- 0.3 vs -8.0 +/- 1.0 mm Hg), suggesting blunted ventilatory responses to hypoxia. Periodic breathing occurred during 9.5% of hypoxic challenges in control infants compared with 37% in ISAM (p = 0.056). Heart rates were significantly higher in the ISAM before, during, and after hypoxic challenges. Hypercapnic challenges (inspired carbon dioxide tension of 60 mm Hg for a maximum of 3 minutes) resulted in arousal in all infants; however, ISAM required a significantly longer exposure to hypercapnia before arousal (mean +/- SEM; 116 +/- 7.8 vs 79 +/- 13.9 seconds; p < 0.02). We conclude that ISAM have an impaired repertoire of protective responses to hypoxia and hypercapnia during sleep, and that this may play a role in their increased risk for sudden infant death syndrome.

Elevated Plasma Norepinephrine Levels in Infants of Substance-Abusing Mothers

Infants of substance-abusing mothers (ISAM) have significant growth and neurodevelopmental abnormalities. The origin of these abnormalities is unknown. We postulated that ISAM have increased sympathetic nervous system tone and altered catecholamine levels. Therefore, we measured plasma norepinephrine, epinephrine, and dopamine levels and the number and receptor affinity of beta-adrenoreceptor binding sites on lymphocytes and alpha-adrenoreceptor binding sites on thrombocytes in 22 otherwise healthy ISAM (age, 2.1 +/- 0.5 months; mean +/- SD) and 15 healthy controls (age, 2.5 +/- 0.8 months). Norepinephrine levels in venous blood were 1.8-fold higher in ISAM than in control infants (6.30 +/- 3.85 nmol/L vs 3.55 +/- 2.45 nmol/L). There were no differences in plasma epinephrine or dopamine levels. There were no differences in the number of binding sites or receptor affinity for beta- and alpha-adrenoreceptors. We conclude that ISAM have elevated circulating norepinephrine levels compared with controls. We speculate that this is associated with increased sympathetic nervous system tone in ISAM and that the absence of adrenoreceptor down-regulation may create catecholamine suprasensitivity.

SUBSTANCE ABUSE AND RISK OF SIDS.

An epidemiologic study in the Los Angeles area suggests that infants of substance-abusing mothers have a substantially elevated risk of sudden infant

Sudden infant death syndrome in infants of substance-abusing mothers

A population-based study was performed to determine whether substance abuse during the perinatal period may be a risk factor for sudden infant death syndrome (SIDS). The incidence of SIDS was studied in 2143 infants of substance-abusing mothers (ISAM) born in Los Angeles County during 1986 and 1987 who were reported to the Los Angeles County Department of Health Services because of a history of drug exposure or positive urine test results in the mother, infant, or both. By comparing the ISAM birth reports with records of autopsy-proven SIDS in Los Angeles County, we found 19 SIDS cases in the population of 2143 ISAM, a SIDS rate of 8.87 cases per 1000 ISAM (95% confidence interval 5.3 to 13.8). This was significantly higher than the SIDS rate for the non-ISAM general population: 396 SIDS deaths among 325,372 live births, an incidence rate of 1.22 cases per 1000 births, p less than 0.00001. The age of ISAM at death was 99 +/- 63 (mean +/- SD) days compared with 91 +/- 52 days for the non-ISAM population (not significant). The incidence of SIDS was significantly greater in male infants, during the winter months, in black infants, and in non-Hispanic white infants in the non-ISAM population. Such differences were not observed in the ISAM group. A greater incidence of symptomatic apnea was reported before SIDS for the ISAM than for the non-ISAM population (22% vs 5.4%, p = 0.022). We conclude that ISAM have a higher incidence of SIDS than the non-ISAM general population. However, it was not possible to separate maternal substance abuse from other confounding variables that may also have had an impact on SIDS risk in the ISAM group.