TY - JOUR
T1 - Lactation and birth spacing in highland new guinea
AU - Wood, James W.
AU - Maslar, Ila A.
AU - Lai, Daina
AU - Johnson, Patricia L.
AU - Campbell, Kenneth L.
N1 - Funding Information:
Special thanks are due to Dr C. Jenkins for developing and field testing the format for recording nursing episodes and for her other help. We also thank P. Heywood, W. Davison and the staff of the Papua New Guinea Institute of Medical Research for their co-operation. Assistance with the radioimmunoassays was provided by J. Gadsby, M. Hepburn and W. Schramm. We thank J. Brainard, W. Butz, J-P. Habicht, A. Hermalin, C. Jenkins, R. Midgley, L. Myers, R. Short and P. Smouse for their comments. Supported by NIH grants F32-GM-O8551, RO1-GM-3O135 and T32-GM-07123, and by grants from the Andrew W. Mellon Foundation.
PY - 1985
Y1 - 1985
N2 - The effects of infant suckling patterns on the post-partum resumption of ovulation and on birth-spacing are investigated among the Gainj of highland New Guinea. Based on hormonal evidence, the median duration of lactational anovulation is 20·4 months, accounting for about 75% of the median interval between live birth and next successful conception (i.e. resulting in live birth). Throughout lactation, suckling episodes are short and frequent, the interval changing slowly over time, from 24 minutes in newborns to 80 minutes in 3-year olds. Maternal serum prolactin concentrations decline in parallel with the changes in suckling patterns, approaching the level observed in non-nursing women by about 24 months post-partum. A path analysis indicates that the interval between suckling episodes is the principal determinant of maternal prolactin concentration, with time since parturition affecting prolactin secretion only in so far as it affects suckling frequency. The extremely prolonged contraceptive effect of breast-feeding in this population thus appears to be due to (i) a slow decline in suckling frequency with time since parturition and (ii) absence of a decline over time in hypothalamic-pituitary responsiveness to the suckling stimulus.
AB - The effects of infant suckling patterns on the post-partum resumption of ovulation and on birth-spacing are investigated among the Gainj of highland New Guinea. Based on hormonal evidence, the median duration of lactational anovulation is 20·4 months, accounting for about 75% of the median interval between live birth and next successful conception (i.e. resulting in live birth). Throughout lactation, suckling episodes are short and frequent, the interval changing slowly over time, from 24 minutes in newborns to 80 minutes in 3-year olds. Maternal serum prolactin concentrations decline in parallel with the changes in suckling patterns, approaching the level observed in non-nursing women by about 24 months post-partum. A path analysis indicates that the interval between suckling episodes is the principal determinant of maternal prolactin concentration, with time since parturition affecting prolactin secretion only in so far as it affects suckling frequency. The extremely prolonged contraceptive effect of breast-feeding in this population thus appears to be due to (i) a slow decline in suckling frequency with time since parturition and (ii) absence of a decline over time in hypothalamic-pituitary responsiveness to the suckling stimulus.
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U2 - 10.1017/S0021932000025190
DO - 10.1017/S0021932000025190
M3 - Article
AN - SCOPUS:84974378708
SN - 0021-9320
VL - 17
SP - 159
EP - 173
JO - Journal of Biosocial Science
JF - Journal of Biosocial Science
IS - S9
ER -
