妊娠に伴う網膜血流量の増加

Increased retinal blood flow during pregnancy

　対象は以前にbidirectional laser Dop-pler法の正常者として測定され，その後妊娠した26歳女子で，妊娠中と分娩後に血流量の測定を行った。測定部位は右眼の下耳側動脈である。Flow pulsatility（収縮期血流速度／拡張期血流速度）は妊娠前には3.2であり，妊娠26週には4.75に増加し，分娩直前まで一定であった。妊娠前と比べ，血流速度と血流量は妊娠22週には変化を認めず，26週に27％と21％，30週に46％と40％，34週に54％と61％，39週に95％と72％の増加を示した。測定値は分娩4週後には，ほとんど妊娠前の値に復帰していた。妊娠に伴い血流量は増加したが，妊娠22週までは増加が認められず，網膜循環には独自の血流調節機能が存在していることが示唆された。

A 26-year-old woman served earlier as healthy volunteer for laser Doppler retinal blood flow studies. She became pregnant and volunteered for further studies during and after pregnancy. We used bidirectional laser Doppler technique to measure the centerline erythrocyte speed (V) along the inferotemporal retinal artery of the right eye. The flow pulsatility, V_systole/V_diastoie, was 3.2 before pregnancy, increased to 4.8 at 26 weeks of pregnancy and stayed constant until delivery. The average blood flow velocity was 5.9cm/sec before pregnancy and increased steadily to a peak of 11.5 cm/sec prior to delivery. The blood flow rate was 31.7μl/min before pregnancy, stayed unchanged at 22 weeks and then increased steadily to a peak of 54.6μl/min prior to delivery. These parameters returned to prepregnancy levels after delivery.