Contraception
46:543-548,
1992
PLASMA PROLACTIN IN RELATION TO MENSTRUAL CYCLE PHASE, ORAL CONTRACEPTIVE USE, AROUSAL TIME AND SMOKING HABITS H. Jemstriim,
MKnutsson,
Department
of Oncology,
P. Taskila,
University
H. Olsson
Hospital, Lund S-221 85, Sweden
Supported with grants from the Swedish Cancer Society, the Medical and the Berta Kamprad’s Foundation.
Faculty
of Lund,
ABSTRACT The study was designed to investigate if modem low dosage combined oral contraceptives were associated with changes in plasma prolactin levels in healthy nulliparous women aged 19-2.5. Plasma prolactin was not significantly correlated to oral contraceptive use, nor to smoking habits. Plasma prolactin was, however, significantly negatively correlated to time since awakening. A significant two-way interaction on prolactin was also seen between smoking and present oral contraceptive use. In our material the mean values of plasma prolactin were higher in the follicular phase than in the luteal phase, although not significantly.
INTRODUCTION Estrogens increase the level of plasma prolactin ( 1) and therefore it has generally been assumed that oral contraceptives (OCs) also augment prolactin levels, although investigations have shown conflicting results ( 2-9 ). It is even more unclear if modem low dosage OCs are associated with changes in plasma prolactin levels. Furtheqthe role of smoking on the pituitary-gonadal function needs to be taken into account,as smoking 10 cigarettes or more per day may lower the mean serum prolactin level by 20% ( 10 ). In order to find out if such changes occur in young women using low dosage OCs.we have interviewed a young group of nulhparous medical students and nurses in training about OC-use and related the plasma pmlactin levels to the OC history after adjusting for time since awakening and smoking history.
MATERIAL AND METHODS Plasma prolactin was analysed in 41 female medical students and 8 nursing studentsThe median age among the women was 22 years (range 19-25).Women who had been pregnant. with a history of a full-term pregnancy, miscarriage or abortion, usage of OCS containing only gestagens, intake of drugs with an impact on the prolactin level, Submitted Accepted
Copyright
for publication for pub1 ication
February September
0 1992 Butterworth-Heinemann
24, 29,
1992 1992
or other hormonal preparations were excluded from the study. A detailed history was taken concerning OC use, smoking habits, menstrual cycle phase, and time of awakening in relation to sample time. Forty-four of the women had regular menstrual cycles, while 5 women had irregular menstrual cycles, i.e. in 10% of the material, the cycle irmgularity ranged between six and twelve days. The menstrual cycle was divided into two phases: follicular and luteal phase. We defined the luteal phase as the last 14 days of each woman’s menstrual cycle. In the material, 21 of the women were present OC users, 14 were former OC users, and 14 had never used oral contraceptives. The OC brands used by the women in this material were of low-dose type and contained both estrogens and progestins. Sixty percent of the ever users used monophasic pills and 40% used triphasic pills. Forty women had never smoked and 9 had ever smoked. The plasma prolactin samples were collected between 8 and 10 am from the medical students and at 11.30 am from the nursing students. They were spun down and kept at -70 degrees C.The samples were analysed by radioimmunoassay at the same laboratory, on two occasions. with an interval of two months. Interassay variation was 7% and intraassay variation 5%. Normal reference value for premenopausal women is
46:543-548,
1992
PLASMA PROLACTIN IN RELATION TO MENSTRUAL CYCLE PHASE, ORAL CONTRACEPTIVE USE, AROUSAL TIME AND SMOKING HABITS H. Jemstriim,
MKnutsson,
Department
of Oncology,
P. Taskila,
University
H. Olsson
Hospital, Lund S-221 85, Sweden
Supported with grants from the Swedish Cancer Society, the Medical and the Berta Kamprad’s Foundation.
Faculty
of Lund,
ABSTRACT The study was designed to investigate if modem low dosage combined oral contraceptives were associated with changes in plasma prolactin levels in healthy nulliparous women aged 19-2.5. Plasma prolactin was not significantly correlated to oral contraceptive use, nor to smoking habits. Plasma prolactin was, however, significantly negatively correlated to time since awakening. A significant two-way interaction on prolactin was also seen between smoking and present oral contraceptive use. In our material the mean values of plasma prolactin were higher in the follicular phase than in the luteal phase, although not significantly.
INTRODUCTION Estrogens increase the level of plasma prolactin ( 1) and therefore it has generally been assumed that oral contraceptives (OCs) also augment prolactin levels, although investigations have shown conflicting results ( 2-9 ). It is even more unclear if modem low dosage OCs are associated with changes in plasma prolactin levels. Furtheqthe role of smoking on the pituitary-gonadal function needs to be taken into account,as smoking 10 cigarettes or more per day may lower the mean serum prolactin level by 20% ( 10 ). In order to find out if such changes occur in young women using low dosage OCs.we have interviewed a young group of nulhparous medical students and nurses in training about OC-use and related the plasma pmlactin levels to the OC history after adjusting for time since awakening and smoking history.
MATERIAL AND METHODS Plasma prolactin was analysed in 41 female medical students and 8 nursing studentsThe median age among the women was 22 years (range 19-25).Women who had been pregnant. with a history of a full-term pregnancy, miscarriage or abortion, usage of OCS containing only gestagens, intake of drugs with an impact on the prolactin level, Submitted Accepted
Copyright
for publication for pub1 ication
February September
0 1992 Butterworth-Heinemann
24, 29,
1992 1992
or other hormonal preparations were excluded from the study. A detailed history was taken concerning OC use, smoking habits, menstrual cycle phase, and time of awakening in relation to sample time. Forty-four of the women had regular menstrual cycles, while 5 women had irregular menstrual cycles, i.e. in 10% of the material, the cycle irmgularity ranged between six and twelve days. The menstrual cycle was divided into two phases: follicular and luteal phase. We defined the luteal phase as the last 14 days of each woman’s menstrual cycle. In the material, 21 of the women were present OC users, 14 were former OC users, and 14 had never used oral contraceptives. The OC brands used by the women in this material were of low-dose type and contained both estrogens and progestins. Sixty percent of the ever users used monophasic pills and 40% used triphasic pills. Forty women had never smoked and 9 had ever smoked. The plasma prolactin samples were collected between 8 and 10 am from the medical students and at 11.30 am from the nursing students. They were spun down and kept at -70 degrees C.The samples were analysed by radioimmunoassay at the same laboratory, on two occasions. with an interval of two months. Interassay variation was 7% and intraassay variation 5%. Normal reference value for premenopausal women is
