Does thermal stress decrease uterine blood flow in hypertensive pregnancies?

The aim of the study was to determine the acute effects of thermal stress on maternal and fetal circulatory responses in normal and hypertensive patients. Therefore we studied 14 healthy pregnant women and 12 women with compromised pregnancies during short-term heat stress using color Doppler ultrasound in addition to conventional follow-up methods. The uterine vascular resistance increased significantly during the exposure in the high-risk pregnancy group without change in the control group. The results of the present study give strong support to our earlier studies that short-term heat stress seems to be safe in uncomplicated pregnancies but may be detrimental in high-risk pregnancies.

Hydatidiform mole in a 56-year-old woman.

We present a rare case of a hydatidiform mole that occurred in a 56-year old woman. The main symptom was prolonged vaginal bleeding, and the gynaecological examination revealed a markedly enlarged uterus. Sonography revealed a 9 x 15 cm large cystic tumour in the pelvis. At operation, a suspicion of trophoblastic disease was arosen. Serum human chorion gonadotropin was still markedly elevated on the fifth postoperative day. After removal of the uterus and adnexae the recovery and the 3-year follow-up have been uneventful.

Effects of short-term thermal stress on plasma catecholamine concentrations and plasma renin activity in pregnant and nonpregnant women.

OBJECTIVE: The purpose of this study was to find out whether the effects of thermal stress on plasma catecholamines and plasma renin activity are altered by pregnancy. STUDY DESIGN: Nonpregnant (n = 15) and pregnant (13 to 14 weeks, n = 23; 36 to 37 weeks, n = 23) healthy women were examined. Samples were taken before the exposure, in the heat chamber (70 degrees C), and during the recovery. The BMDP statistical software was used. RESULTS: The concentration of epinephrine in plasma increased significantly only in the nonpregnant group. The epinephrine concentrations in the pregnancy groups increased most in the subjects who felt discomfort during or after the exposure. Plasma norepinephrine concentrations increased without significant differences between the groups. Plasma renin activity increased in each group, but the increases were significantly lower in the pregnancy groups as compared with the nonpregnant group. CONCLUSIONS: Pregnancy does not alter the thermally induced increase in norepinephrine release. The adrenaline response is mostly dependent on the mental discomfort. The plasma renin activity response to thermal stress is blunted during pregnancy.

Haemodynamic response to moderate thermal stress in pregnancy.

The effect of a moderate heat stress on cardiovascular responses was studied: group I consisted of 15 healthy non-pregnant women, group II of 23 women 13-14 weeks pregnant and group III of 23 women 36-37 weeks pregnant. Heart rate, stroke volume, cardiac output, arterial blood pressure and peripheral vascular resistance were recorded every 5-10 minutes during a resting period (20 min, 21-23 degrees C) followed by heat stress (20 min, 70 degrees C, 15% relative humidity) and a recovery period (45 min, 21--23 degrees C). The rectal temperature increased 0.3-0.4 degrees C in each group during thermal stress. The heart rate before stress was highest in the advanced pregnancy group but increased almost identically in each group by 36--37 beats per minute during stress and approached starting values during recovery. There were no major changes in stroke volume during the experiment in any group nor were there any differences between the three groups. Arterial blood pressure did not change significantly in any group during the experiment; the differences between the groups were minimal. Peripheral vascular resistance began to fall at the start of the thermal stress and returned to prestress levels at the end of the recovery period. There were no differences between the groups in proportional changes of peripheral resistance. We conclude that pregnancy does not alter the cardiovascular responses to moderate thermal stress.