The effect of multiple pregnancies on lumbar bone mineral density in Japanese women.
OBJECTIVE
To elucidate the effect of multiple pregnancies on lumbar spine bone mineral density (BMD).


METHODS
The BMD of the lumbar spines (L2-L4) of 1,113 healthy women was measured within 7 days of childbirth. In addition 113 women had spine BMD measurements after their next delivery.


RESULTS
In the cross-sectional study, there was no apparent effect of parity on lumbar BMD. In the longitudinal study, the mean BMD after the next delivery was significantly higher than that after the initial delivery (1.019 +/- 0.115 g/cm(2) vs. 1.006 +/- 0.117 g/cm(2), P = 0.001, paired t test) with a percent change (DeltaBMD%) of 1.4 +/- 4.2%. Multiple regression analysis to identify independent predictors of DeltaBMD% showed a negative correlation with maternal age at the subsequent delivery (P = 0.033) but no correlation of DeltaBMD% with the length of lactation between the scans.


CONCLUSIONS
Multiple pregnancies may not reduce maternal lumbar BMD, although the percentage decrease in BMD was greater in older women at the subsequent delivery. The length of lactation between the scans had no effect on these results.
Department of Obstetrics and Gynecology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Niigata 951-8510, Japan.
H
H
Matsushita
T
T
Kurabayashi
M
M
Tomita
A
A
Honda
K
K
Takakuwa
K
K
Tanaka
D001835:Body Weight; D015519:Bone Density / Q000502:physiology*; D005260:Female; D006801:Humans; D007564:Japan; D008159:Lumbar Vertebrae / Q000502:physiology*; D008875:Middle Aged; D010298:Parity; D011247:Pregnancy; D011272:Pregnancy, Multiple / Q000502:physiology*; D015430:Weight Gain; D044465:White People