Interesting Article on Superovulation and Preterm Delivery....

[Twins_Squared]

Hi,

I was forwarded a copy of this article from a dear friend, Cubanita, who rec'd a copy from our mutual Peri. This is NOT intended as medical advice, but I have rec'd a PM after mentioning it in another thread to someone and wanted to post it for information purposes.

The article is based on a study of singleton pregnancies and appeared in "Obstetrics & Gynecology" magazine, Vol 92, No. 1, July 1998. It is a highly clinical article, but the general gyst of it is that superovulation (which is what happens in IUI stim cycles and IVF cycles) was found in this study to have a correlation to increased Relaxin levels (a hormone) and a prediction toward premature birth. It discusses the medical hypothesis that, "high concentrations of relaxin predispose patients to preterm labor by a relaxin-induced form of cervical incompetence."

Here's the article (sorry its long)
Elevated Maternal Serum Relaxin
Concentrations Throughout Pregnancy in
Singleton Gestations After Superovulation
TAONEI I. MUSHAYANDEBVU, MD, LAURA T. GOLDSMITH, PhD,
STANLEY VON HAGEN, PhD, NANETTE SANTORO, MD, DEBORAH THURSTON, RN,
AND GERSON WEISS, MD
Objective: To test the hypothesis that superovulation results
in elevated maternal circulating relaxin concentrations
throughout the second and third trimesters of pregnancy,
independent of the pattern of hCG secretion.
Methods: Two groups of women with singleton gestations
were studied: a group of nine women who achieved pregnancy
after stimulation with human menopausal gonadotropin
and a group of six women who achieved pregnancy
without prior stimulation. Peripheral blood samples were
drawn approximately every 5 weeks throughout the second
and third trimesters. Serum relaxin concentrations were
measured using a human relaxin–specific enzyme-linked
immunosorbent assay; hCG was measured by an immuno-
fluorometric assay.
Results: The stimulated group had significantly higher
relaxin levels throughout pregnancy (P 5 .007, multivariate
analysis of variance) than did nonstimulated controls. The
mean relaxin level in stimulated patients was 1.78 ng/mL
(95% confidence interval [CI] 1.5, 2.17) and in nonstimulated
subjects the level was 0.73 ng/mL (95% CI 0.59, 1.25). Spline
fits demonstrated that stimulated patients had higher relaxin
levels throughout the second and third trimesters. There was
no significant difference in hCG concentrations between the
two groups (P 5 .61).
Conclusion: In singleton gestations after superovulation,
maternal serum relaxin concentrations are significantly
higher throughout the second and third trimesters of pregnancy.
These differences are independent of the pattern of
hCG secretion. It appears that luteal relaxin secretion is
controlled by factors in addition to hCG. (Obstet Gynecol
1998;92:17–20. © 1998 by The American College of Obstetricians
and Gynecologists.)
Relaxin, a peptide hormone consisting of an A chain
and a B chain linked by two disulfide bonds, is coded
for by two nonallelic human relaxin genes, H1 and H2,
which reside on the short arm of chromosome nine.1 H2
is the major relaxin gene and is expressed in the corpus
luteum of pregnancy.2 Evidence suggests that the synthesis
and secretion of relaxin in vivo is under the
control of endogenous hCG.3 It also has been demonstrated
that hCG stimulates relaxin secretion in vitro.4
The corpus luteum of pregnancy is the sole source of
circulating relaxin in pregnant women. Proposed roles
for circulating relaxin during pregnancy include maintenance
of myometrial quiescence before labor, facilitation
of stromal remodeling during the period of uterine
growth, and promotion of cervical softening and connective
tissue changes.5
Study of the secretion pattern of relaxin during
spontaneous singleton pregnancies indicated that levels
are highest during the first trimester, increasing to peak
levels between the 8th and 12th weeks of pregnancy
and gradually decreasing to stable levels of approximately
0.5– 0.8 ng/mL for the duration of pregnancy.6
Weiss et al7 demonstrated previously that women who
have had ovulation induction have elevated circulating
relaxin levels in the first trimester of pregnancy and are
at increased risk of premature delivery. Although relaxin
levels were higher during the first trimester in
singleton pregnancies as a result of ovarian stimulation,
7 it is not known whether elevated levels are
maintained into the second and third trimesters.
The aim of the present study was to test the hypothesis
that antecedent superovulation, even in singleton
pregnancies, results in elevated circulating relaxin concentrations
during the second and third trimesters of
pregnancy. We measured maternal serum relaxin con-
From the Departments of Obstetrics and Gynecology and Pharmacology
and Toxicology and the Division of Biostatistics, Department of
Preventive Medicine and Community Health, New Jersey Medical
School, Newark, New Jersey.
Supported by grant HD 22338 from the National Institutes of Health.
17 VOL. 92, NO. 1, JULY 1998 0029-7844/98/$19.00
PII S0029-7844(98)00091-X
centrations during the second and third trimesters in
women with singleton pregnancies who had undergone
superovulation and compared them with maternal serum
relaxin levels in a group of untreated pregnant
women with singleton gestations. To exclude the possibility
that any anticipated differences in relaxin secretion
between the two groups might be due to differences
in the pattern of hCG secretion, we measured
circulating hCG levels in both trimesters in both groups
of women.
Materials and Methods
The participants in this study were receiving care from
the fertility and pregnancy services of New Jersey
Medical School, Newark, New Jersey. The study was
approved by the Institutional Review Board of the
University of Medicine and Dentistry of New Jersey–
New Jersey Medical School. All participants gave written
informed consent. Fifteen subjects were recruited
for the study, representing all the available volunteers.
They were private referral patients from our fertility
service who elected to receive obstetric care at our
institution. Nine patients had undergone superovulation
therapy; their mean age was 38.3 years (range
31–44), and all nine women were white. Seven were
stimulated with human menopausal gonadotropin
(hMG) after suppression with leuprolide acetate, and
two underwent ovarian stimulation with hMG without
prior suppression with leuprolide acetate. All patients
in the stimulated group received 5000 U of hCG to
induce ovulation, followed by a dose of 2500 U 6 days
later for luteal support. The six control subjects had
achieved singleton pregnancies without prior superovulation
therapy. Their mean age was 34 years (range
28–42); one subject was Indian, one was Chinese, and
four subjects were white. They did not receive any hCG.
Blood samples were obtained from each subject approximately
every 5 weeks throughout the second and third
trimesters. Blood was collected into glass tubes and
centrifuged, and the serum was stored at –20C until
assayed.
The second trimester was defined as weeks 14–28 of
pregnancy and the third trimester as any gestation after
28 weeks. Gestational age was calculated in completed
weeks from the 1st day of the last normal menstrual
period and confirmed by physical and first-trimester
ultrasound examination. Term was defined as 38–42
completed weeks of pregnancy.
Relaxin concentrations were measured in each serum
sample using a human relaxin–specific, homologous
enzyme-linked immunosorbent assay whose sensitivity
was 20 pg/mL. Relaxin levels in all samples for this
study were measured in a single assay run and each
sample was analyzed in duplicate. Synthetic human H2
relaxin was used as the standard, a goat anti-human
relaxin polyclonal antibody was used as the coat antibody,
and a horseradish peroxidase–conjugated rabbit
anti-human relaxin polyclonal antibody was used as the
sandwich antibody. These reagents were provided gratuitously
by Genentech Inc. (South San Francisco, CA).
The intra-assay and interassay coefficients of variation
were 5.8 and 13.3%, respectively. This assay has been
used previously to measure circulating relaxin levels in
women.8,9 Human chorionic gonadotropin was measured
using a Dissociation Enhanced Lanthanide
Fluoro-Immunoassay (Wallac Inc., Gaithersburg, MD).
Intra-assay and interassay coefficients of variation were
4.6 and 8.0%, respectively.
Preliminary exploration of the data revealed that both
the relaxin and hCG concentrations were not normally
distributed at the various time points. Both responses
were re-expressed as log10 and then became log normal.
All statistical analyses were performed using these
transformations and the resulting estimates subsequently
were expressed back into their original units
when appropriate. We analyzed data as repeatedmeasures
analyses using the method of multivariate
analysis of variance. Statistical significance (a) was
declared at the 5% level as long as the power (1-b) was
above 60%. The actual powers ranged from 85% to 93%
for those tests involving relaxin levels in stimulated
versus nonstimulated patients. The power for the studies
involving leuprolide plus hMG versus the studies
involving hMG alone ranged from 7% (relaxin) to 80%
(hCG). A power analysis indicated that we could detect
differences in relaxin as large as 1.7 ng/mL at 70%
power and in hCG as large as 4000 IU at 78% power.
The data depicted in Figure 1 were fitted to relaxin in
the log10 transformed units using a cubic spline smoother10
set at l 5 10,000 flexibility (moderately stiff). This
technique allowed us to search for patterns in the data
that were more general than a straight line or other
Figure 1. A cubic spline smoother set at l 5 10,000 flexibility (moderately
stiff) to illustrate differences in relaxin levels between stimulated
(solid line, squares) and nonstimulated (dashed line, Xs) groups over
gestational age.
18 Mushayandebvu et al Ovarian Stimulation and Relaxin Obstetrics & Gynecology
mathematically imposed equation. The smoothing technique
is used to attempt to find a “fitted” value yi that
portrays the middle of the empirical distribution of Y at
X 5 xi, that is, to determine roughly the shape of the
expected values of the distribution of Y across X. All
statistics were performed using JMP statistical software
(SAS Institute, Cary, NC) run on a Macintosh computer
(Apple Computers, Cupertino, CA).
Results
Relaxin was detectable in the serum of all subjects in the
study. Compared with controls, the stimulated group
had significantly higher relaxin levels at each stage of
gestation as determined by a repeated-measures approach
(P 5 .007). There was no detectable trimester
effect, ie, changes in relaxin during the second and third
trimesters were not of a magnitude that would confound
or mask the differences between stimulated and
nonstimulated patients (P 5 .47).
Spline fits were done to get at any underlying curvature
and to determine whether the levels in stimulated
patients remained higher than those in nonstimulated
patients, even though the overall trend was a decrease
in circulating relaxin as the gestational age increased.
These fits are depicted in Figure 1 and confirm the
results of the analysis discussed earlier. The stimulated
group had higher relaxin levels for the entire duration
of pregnancy. Circulating relaxin in both stimulated
and nonstimulated groups appeared to decrease with
gestational age. The overall average predicted relaxin
level (ie, least-square means) in stimulated patients was
1.78 ng/mL (95% confidence interval [CI] 1.5, 2.17). The
overall average predicted relaxin level in controls was
0.73 ng/mL (95% CI 0.59, 1.25).
Human chorionic gonadotropin also was detected in
all patients. There was no significant difference in mean
hCG concentrations between the stimulated and nonstimulated
groups (P 5 .61). Cubic spline fits depicted
in Figure 2 show that in both the stimulated and
nonstimulated groups, hCG levels did not have significantly
different patterns of secretion during the second
and third trimesters.
To exclude the possibility that suppression with
leuprolide was a factor among patients undergoing
ovarian stimulation, we compared relaxin and hCG
levels between the two patients treated with hMG alone
and the seven patients treated with leuprolide acetate
and hMG. There were no significant differences in
relaxin levels (P 5 .21) between the groups. There
appeared to be a small (4000 IU), statistically detectable
(P 5 .007) difference in hCG levels between the two
groups. Most of this difference was in the third trimester.
One patient in the stimulated group delivered prematurely
at 36 weeks and the rest delivered at term. All
nonstimulated group patients delivered at term. No
patient delivered postterm.
Discussion
Our findings demonstrate that ovarian stimulation with
hMG, even in singleton pregnancies, results in elevated
circulating relaxin concentrations during the second
and third trimesters when compared with nonstimulated
controls. The observed elevated serum relaxin
levels in the stimulated group are similar to those
described in multiple gestations after menotropin therapy,
suggesting that the elevation is due principally to
the effect of the hMG therapy.11 Human menopausal
gonadotropin induces polyovulation with the formation
of multiple corpora lutea.
We also found that high relaxin concentrations in the
second trimester tend to be associated with elevated
third-trimester relaxin levels. We demonstrated previously
that elevated first-trimester relaxin levels in pregnant
women after ovarian stimulation predict prematurity.
7 In addition, Petersen et al12 reported that, in
spontaneous singleton pregnancies, high maternal serum
relaxin concentrations in the 30th week of pregnancy
are associated significantly with preterm labor. It
had been hypothesized previously that high concentrations
of relaxin predispose patients to preterm labor by
a relaxin-induced form of cervical incompetence.11 Because
we previously have demonstrated an association
between elevated first-trimester relaxin levels and increased
risk of prematurity,7 the fact that elevated
maternal relaxin concentrations are maintained into the
second and third trimesters may help explain the increase
in prematurity risk. Given that hyperrelaxinemia
is present in both singleton and multiple gestations
after menotropin therapy, such ovarian stimulation
Figure 2. A cubic spline smoother set at l 5 10,000 flexibility (moderately
stiff) to illustrate differences in hCG concentrations between the
stimulated (solid line, squares) and nonstimulated (dashed line, Xs)
groups over gestational age.
VOL. 92, NO. 1, JULY 1998 Mushayandebvu et al Ovarian Stimulation and Relaxin 19
appears to increase the risk of prematurity in all pregnancies,
whether multiple or singleton.
Human chorionic gonadotropin stimulates relaxin
secretion in vivo during the late luteal phase3 and from
luteinized human granulosa cells in vitro.4 Given that
hCG levels were similar in both stimulated and nonstimulated
patients in the present study, differences in
the levels of relaxin appear to be independent of the
pattern of hCG secretion, suggesting that luteal relaxin
during the second and third trimesters is controlled by
additional factors besides hCG. Supportive of this thesis
are the findings of Rajaniemi et al,13 who demonstrated
that the concentration of hCG receptors in luteal cells
was lower at term than during the menstrual cycle,
possibly because of receptor down-regulation by the
high serum hCG levels.13 Marsh and LeMaire14 also
demonstrated that hCG had very little effect on steroid
and cyclic adenosine monophosphate production in the
corpus luteum of late pregnancy when compared with
corpora lutea of the menstrual cycle. Goldsmith et al15
suggested that progesterone production by the term
corpus luteum is under the control of additional factors
besides hCG. Likewise, other factors in addition to hCG
may contribute to relaxin secretion in the second and
third trimesters.
In a rodent model, the relaxin effect of promoting
cervical ripening is estrogen dependent.16 Mercado-
Simmen et al17 hypothesized that the increasing estrogen
levels throughout pregnancy increase relaxin receptors
or in some other way increase relaxin sensitivity
such that serum relaxin becomes more effective toward
the end of pregnancy.
We conclude that hMG treatment in singleton gestations
induces significantly higher relaxin concentrations
throughout the second and third trimesters of pregnancy.
Such differences are independent of the pattern
of hCG, suggesting that luteal relaxin secretion is controlled
by additional factors besides hCG. We acknowledge
that this study has a limited sample size. Given
that we have demonstrated previously that elevated
first-trimester relaxin levels are associated with an
increased risk of premature delivery,7 maintenance of
elevated maternal relaxin concentrations into the second
and third trimesters may be responsible for the
increase in such risk.

To be continued:

[Twins_Squared]

Part II:

References:
1. Crawford RJ, Hudson P, Shine J, Niall HD, Eddy RH, Shows TB.
Two human relaxin genes are on chromosome nine. EMBO J
1984;3:2341–5.
2. Eddie LW, Bell RJ, Lester A, Geier M, Bennett G, Johnston PD, et
al. Radioimmunoassay of relaxin in pregnancy with an analogue of
human relaxin. Lancet 1986;1:1344 –9.
3. Quagliarello J, Goldsmith L, Steinetz B, Weiss G. Induction of
relaxin secretion in nonpregnant women by human chorionic
gonadotropin. J Clin Endocrinol Metab 1980;51:74 –7.
4. Gagliardi C, Goldsmith LT, Saketos M, Weiss G, Schmidt C.
Human chorionic gonadotropin stimulation of relaxin secretion by
luteinized human granulosa cells. Fertil Steril 1992;58:314 –20.
5. MacLennan AH. The role of relaxin in human reproduction. Clin
Reprod Fertil 1983;2:77–95.
6. Bell RJ, Eddie LW, Lester AR, Wood EC, Johnston PD, Niall HD.
Relaxin in human pregnancy serum measured with an homologous
radioimmunoassay. Obstet Gynecol 1987;69:585–9.
7. Weiss G, Goldsmith LT, Sachdev R, Von Hagen S, Lederer K.
Elevated first-trimester serum relaxin concentrations in pregnant
women following ovarian stimulation predict prematurity risk and
preterm delivery. Obstet Gynecol 1993;82:821– 8.
8. Haning RV, Canick JS, Goldsmith LT, Shahinian KA, Erinakes NJ,
Weiss G. The effect of ovulation induction on the concentration of
maternal serum relaxin in twin pregnancies. Am J Obstet Gynecol
1996;174:227–32.
9. Haning RV, Goldsmith LT, Seifer DB, Wheeler C, Frishman G,
Sarmento J, et al. Relaxin secretion in in vitro fertilization pregnancies.
Am J Obstet Gynecol 1996;174:233– 40.
10. Eubank RL. Spline smoothing and nonparametric regression. New
York: Marcel Dekker, 1988.
11. Haning RV, Steinetz BG, Weiss G. Elevated serum relaxin levels in
multiple pregnancy after menotropin treatment. Obstet Gynecol
1985;66:42–5.
12. Petersen LK, Skajaa K, Uldberg N. Serum relaxin as a potential
marker for preterm labour. Br J Obstet Gynaecol 1992;99:292–5.
13. Rajaniemi HJ, Rennberg L, Kaupila S, Ylostalo P, Jalkanen M,
Saastamoinen J, et al. Luteinizing hormone receptors in human
ovarian follicles and corpora lutea during menstrual cycle and
pregnancy. J Clin Endocrinol Metab 1981;52:307–13.
14. Marsh JM, LeMaire WJ. Cyclic AMP accumulation and steroidogenesis
in the human corpus luteum, effect of gonadotropins and
prostaglandins. J Clin Endocrinol Metab 1974;38:99 –106.
15. Goldsmith LT, Essig M, Sarosi P, Beck P, Weiss G. Hormone
secretion by monolayer cultures of human luteal cells. J Clin
Endocrinol Metab 1981;53:890 –2.
16. Kroc RH, Steinetz BG, Beach VL. The effects of estrogens, progestagens,
and relaxin in pregnant and nonpregnant laboratory
rodents. Ann N Y Acad Sci 1959;75:942– 80.
17. Mercado-Simmen RC, Goodwin B, Ueno MS, Yamamoto SY,
Bryant-Greenwood GD. Relaxin receptors in the myometrium and
cervix of the pig. Biol Reprod 1982;26:120–8.
Address reprint requests to:
Gerson Weiss, MD
Department of Obstetrics and Gynecology
New Jersey Medical School
185 South Orange Avenue–MSB E-506
Newark, NJ 07103–2714
E-mail: weissge@umdnj.edu
Received August 13, 1997.
Received in revised form January 22, 1998.
Accepted February 13, 1998.
Copyright © 1998 by The American College of Obstetricians and
Gynecologists. Published by Elsevier Science Inc.
20 Mushayandebvu et al Ovarian Stimulation and Relaxin Obstetrics & Gynecology

[ajbear]

Okay, I will be honest - I did not read everything - but I think it is just scary, scary sutff. To want a baby sooooo bad, to end up with multiples, and to have preterm births - wrong, wrong, wrong.

[Twins_Squared]

(((Amanada))),

Hugs, the article was hard for me to read, too, but I did want to share it nonetheless. I think the RE world might need to look at this more seriously.

[catmom]

That's really interesting. I've been persistent in bugging my OB about ensuring my cervix isn't shortening because I have a couple of risk factors for IC (prior LEEP procedure & current twin pregnancy - and placenta previa might be a factor too). It looks like the fact that my twins were conceived via IVF is yet another IC risk factor, which is really good to know.

Thanks for posting this article!

[BC-tysa]

This is a little bit different, but my RE was telling me about a new practice that has women receiving PIO shots weekly starting at 20 weeks. It is thought that this will reduce the chance of PT labor as well. For the same reason as it helps early in IVF, keeps the uterus more relaxed.

Just something to think about.