Table II.

HRV data among the 3 groups (observed means and standard errors)

	Group 1 (Cocaine)	Group 2 (Other drugs)	Group 3 (No drugs)	P
Sample size (n)
Birth	95	110	97
2–6 months	71	89	77
HR
Birth	132.75(0.93)	130.27 (0.85)	130.67 (0.92)	.127
2–6 months	142.74(1.08)¶	141.88 (0.95)¶	143.70(1.04)¶	.431
RMSSD
Birth	20.33 (0.63)	22.04 (0.65)	21.19 (0.59)	.088
2–6 months	21.97 (0.80)¶	20.39 (0.45)	19.65 (0.56)	.022§
SDNN
Birth	41.88(1.15)	47.64(1.15)	46.82(1.23)	.002†‡
2–6 months	49.94(1.14)¶	49.07 (1.00)	47.82(1.04)	.297
HF
Birth	50.32 (3.89)	69.36 (5.54)	59.04 (4.37)	.006‡
2–6 months	75.54 (7.49)¶	62.15 (4.49)	60.63 (5.07)	.089
LF
Birth	122.99 (8.89)	161.23 (10.69)	138.61 (8.13)	.012‡
2–6 months	150.34(11.94)¶	145.34 (9.74)	134.09 (7.97)	.271
Total
Birth	872.97 (59.76)	1196.00 (83.01)	1125.44 (79.70)	.234
2–6 months	1224.38 (93.91)¶	1215.15(127.79)	1097.37(92.84)	.021 §
VLF
Birth	251.40 (26.15)	303.65 (23.55)	271.36 (21.07)	.858
2–6 months	208.98 (20.61)	276.45 (60.54)	211.15 (32.30)¶	.263
ULF
Birth	472.46(32.81)	661.47 (57.85)	656.79 (59.75)	.176
2–6 months	792.69 (65.08)¶	732.27 (65.24)	691.77 (59.87)	.013§||
SNN-50
Birth	4320.09 (404.41)	5743.43 (468.23)	4835.27 (425.12)	.047‡
2–6 months	6565.65 (709.79)¶	4905.06 (406.52)	4752.39 (519.28)	.025§
SDNNI
Birth	27.78 (0.90)	31.33 (0.91)	30.46 (0.95)	.035‡
2–6 months	29.61 (0.86)	29.18(0.71)	28.23 (0.66)	.288
SDANN
Birth	31.89(1.29)	35.62(1.29)	35.16 (1.01)	.078
2–6 months	39.18(1.53)¶	38.77 (1.22)	36.99 (0.98)	.097

Values are presented as mean (SE), unless otherwise indicated.

^*P values are calculated from the repeated measures analyses adjusting for body surface area.

^†Cocaine versus no drugs at birth.

^‡Cocaine versus other drugs at birth.

^§Cocaine versus no drugs at 2 to 6 months.

^||Cocaine versus other drugs at 2 to 6 months.

^¶Significant change at 2 to 6 months of age from birth (P < .015).