Intro
With female puberty, women reach fertility through the beginning of the monthly
reproductive cycles that prepare the body for pregnancy ( Moore, 2004 ). The menstrual cycle consists of all the
physiological changes caused by the integrated action of the
cortex-hypothalamus-pituitary-ovarian-uterine axis, and ends and begins with
menstruation. The patterns of menstrual bleeding are considered relevant indicators
of reproductive health, but few studies focus specifically on these aspects.
Menstrual irregularities in the reproductive life of extremes are well known,
however cycle variability in patients within reproductive age is not so clear.
Bleeding patterns are hypothetically associated with hormonal fluctuations during
the cycle. In the medical history of couple with infertility are the usual questions
about the patient's menstrual regularity. Information is often based on the
patient's memory, sometimes caught off guard by the question. The aim of this study
is to assess whether the information on menstrual regularity is consistent with the
assessment of the presence or absence of ovulation and if it is important as a
component of the patient's clinical history.
The menstrual cycle can be divided into three phases: the follicular or
proliferative stage, ovulation, and the luteal or secretory phase. The
luteal phase has a fixed duration of 14 days, while the follicular phase can
vary within a normal cycle. Ovulation is what defines a regular cycle. Both
extra and intraovarian factors regulate folliculogenesis and there should be
a balance between them ( Artini et
al ., 2007 ). Any imbalance between the extra and
intra ovarian factors may result in abnormal folliculogenesis ( Frank et al . 2008 ).
Among ovarian factors, one of the most, if not the most important, is the
hypothalamus action, secreting the gonadotropin regulating hormone (GnRH) in
pulses, which is transported to the anterior pituitary, where the cells
produce, store, and secrete both the follicle-stimulating hormone (FSH) as
well as the luteinizing hormone (LH). These hormones stimulate the ovaries
to develop a dominant follicle, which secretes increasing levels of
estrogen, which in turn cause endometrium proliferation. Estrogen inhibits
the secretion of gonadotropins in the anterior pituitary and hypothalamus by
indirect inhibition (negative feedback), and decreases the levels of LH and
FSH. Above a certain level of estrogen, negative feedback is reversed and
the release of LH from the pituitary gland is stimulated. This "LH peak"
triggers ovulation. After ovulation, the remaining follicular cells in the
ovary luteinize and form the corpus luteum, which secretes estrogen, but
predominantly progesterone. This hormone, in turn, transforms the
endometrium into a secretory and spongy tissue, necessary for the
implantation of the fertilized ovum. If there is no implantation, human
chorionic gonadotropin is not produced, and the corpus luteum regresses.
Falling levels of estrogen and progesterone derivatives of the corpus luteum
causes sloughing of the endometrium and thus menstruation.
Changes in the system can result in changes in ovulation, which will lead to
changes in the menstrual cycle ( Speroff
& Fritz, 2005 ; Popat,
2008 ; Gray, 2013 ). This
gonadotropin control process operates in the microenvironment of a follicle;
however, the composition of the fluid mainly influences oocyte quality, and
not so much the menstrual cycle itself ( Chang
et al ., 2002 ; Salmassi et al ., 2005 ).
The United Nations define reproductive health as a complete physical, mental
and social wellbeing, and not merely the absence of disease or infirmity in
all matters relating to the reproductive system and to its functions and
processes ( United Nations, 1996 ).
Infertility is a disease of the reproductive system, defined by the
inability to achieve a clinical pregnancy after 12 months or more of
regular, unprotected sexual intercourse ( ASRM, 2013 ; Zegers-Hochschild
et al ., 2009 ; NICE, 2013 ). According to the American Society of
Reproductive Medicine and the AHRQ (Agency for Healthcare Research and
Quality) in the United States, because of the decline in fertility and
increased time to conception after the age of 35, women aged above 35 years
of age should be referred to the investigation of infertility after six
months of trying to get pregnant without success ( Liu & Case, 2011 ; ASRM, 2013 ). The WHO estimates that 48.5 million couples
worldwide are infertile, and that between 1990 and 2010, the prevalence of
primary and secondary infertility changed little in most of the planet
( Mascarenhas et al .,
2012 ). It is estimated that 7.4% of American couples are
infertile, and in the world there is up to 15% of people with some fertility
disorder, especially in industrialized nations ( Sharma et al ., 2013 ). Infertility
should, therefore, be considered a disease process worthy of investigation
and treatment. In the UK the principal causes of infertility factors are:
men's factors (30%), ovulatory disorders (25%), tubal lesions (20%), uterus
or peritoneal changes. Approximately 25% of infertility cases are of unknown
etiology and in about 40% of cases, both partners had changes ( NICE, 2013 ). The key features are
regular menstrual cycles, frequency, intensity and duration of flow, but
each of these characteristics shows considerable variability.
The nomenclature of menstrual disorders suffered a series of recommendations,
eliminating Latin American terms of imprecise meaning, at the World Congress
of Gynecology and Obstetrics of the International Federation of Gynecology
and Obstetrics in Cape Town in 2009. If the interval between periods varies
over 20 days, the cycle is considered irregular. As to frequency, the cycle
is considered normal if the interval between the periods is between 24 and
38 days, infrequent menstrual bleeding being the name given to one or two
bleeding episodes within a period of 90 days, and frequent menstrual
bleeding represents more than four bleeding episodes during the same period
in a given year. The duration of bleeding is considered normal if it is 4.5
to 8 days, and it is called abbreviated when it is below 4.5 days and
extended if the duration is over 8 days. The normal volume is empirical and
objectively perceived by the woman, being normal for a volume of 5 to 80ml
of monthly blood loss, mild if less than 5 ml and accentuated above 80ml
( Fraser et al .,
2011 ). Table 1 summarizes
these recommendations.
Clinical dimensions of menstruation and menstrual cycle, and
description of normal limits
Fraser et al .,
2011
Results
Only the variable with FSH values had a normal distribution curve
( P > 0.05) according to the Shapiro-Wilk test. For this variable,
there was the parametric t-test to assess the similarity between the groups. The
other variables showed values with non-normal distribution ( P
<0.05), and submitted to the Mann-Whitney's test. The groups were subjected to
statistical tests to see whether they were similar to the average of the variables
desirable for the pairing. Therefore, all variables of interest were matched to
ensure the homogeneity between the case and control groups.
There were 199 patients who reported regular cycles and 29 who reported irregular
cycles. Among the 199 patients who reported having regular menstrual cycles,
113(57.78%) ovulated upon ultrasound monitoring and 86 (42.22%) patients did not.
Among the 29 patients who reported having irregular cycles, 24 (82.76%) did not
ovulate upon the cycle monitoring. Therefore, the patients who self-reported having
irregular cycles had more than six times the likelihood of not ovulating in a
menstrual cycle (Odds Ratio= 6.307). The chi-square Fisher test was found
significant ( P <0.0001) ( Table
2 ).
Discussion
Menstruation can be conceptualized as the resulting periodic bleeding cycle ( Deligeoroglou & Tsimaris, 2010 ). The ovarian
cycle, because of the importance in steroidogenesis, and the endometrial cycle
reflecting the end of the physiological changes of the shaft in the endometrium,
name the phases of the menstrual cycle. Therefore, the proper functioning of the
cortex, hypothalamic-pituitary-ovarian, endometrial axis is reflected on the
regularity of menses and ovulation ( Popat et
al ., 2008 ) and concludes in primary closing events for
reproductive purposes: ovulation physiological endometrial changes and formation of
the corpus luteum.
The fertility rate of women with long or irregular cycles is smaller, even in women
with normal body mass index ( Jensen et
al ., 1999 ). Infertility of ovulatory cause can reach up to a
quarter of infertility etiologies and one of the questions in the clinical history
of the patient is about the perception of the regularity of menstrual cycles.
Evaluation of menstrual regularity, however, may not be a safe clinical parameter
for the diagnosis of ovulation; there may be a lack of ovulation in women with
regular menstrual cycles, and ovulation present in those with irregular menstrual
cycles. In patients with amenorrhea, lack of ovulation is expected and widely known
( Lauritsen et al , 2015 ).
But many women cannot properly report on their cycle interval, days and amount of
bleeding, stating only that the menstrual cycle is irregular. The assessment of
ovulation through complementary examination such as ultrasound becomes a more
accurate diagnosis of the presence of ovulation and the findings of Malcon & Cumming (2003) cast doubt on the
concept of anovulatory cycles in eumenorrheic women ( Malcolm & Cumming, 2003 ). Eumenorrheic women may have anovulatory
cycles, like so, there is no absolute relationship between menstrual regularity and
ovulation, and the anovulation may be a subclinical cycle dysfunction ( Hambridge et al ., 2013 ). Carmina & Lobo (1999) observed 20 to 50% of
anovulatory cycles in patients with self-reported regular cycles, but also observed
that patients with prolonged interval between cycles do not necessarily have
anovulation.
Another motivation for this study was to strengthen, together with current data, the
need to take a detailed medical history, important for the initial investigation of
infertility by the clinician. With technological advances, the clinical history
often goes into the background, and the general gynecologist feels inhibited and
uncertain about the importance of the anamnesis.
In our study, the patients who reported having regular menstrual cycles, correlated
with ovulation monitoring showed the presence of ovulation, and who reported
irregular menstrual cycles showed correlation with lack of ovulation on ultrasound
scans. In the absence of other diseases, the report that the menstrual cycle is
irregular, can facilitate and even drive the reasoning for the diagnosis of
anovulation, given the significance of the statistical results.
Conclusions
The patient's information in the clinical interview about the presence of regular or
irregular menstruation correlates with the presence or absence of ovulation. It is a
question that should continue to be asked when collecting information from the
clinical history, and should be valued when looking for the etiology of infertility.
This report would be important to guide the diagnosis of ovulatory regularity of the
patient.
Materials|Methods
Cross-sectional
The study was carried out at the Human Reproduction Laboratory of the University
Hospital, which serves patients of the Brazilian Public Healthcare System (SUS).
The study was approved by the Ethics Committee of the University Hospital -
Federal University of Goias. The following biochemical tests were requested for
all patients: FSH between 2nd and 4th day of the cycle, LH, prolactin and
thyroid-stimulating hormone (TSH). Ovulation monitoring was performed starting
at the 2nd to the 5th day of the cycle, with reviews at the 10th day of the
cycle until ovulation happened or until day 16, if there were no dominating
follicles developing or follicular collapse. The ultrasound equipment used was a
LOGIQ P6 model, manufactured by General Electrics (GE). The examinations were
performed by doctors of the Human Reproduction Center HC-UFG.
We evaluated 413 ultrasound monitoring reports of ovulation conducted between
January 2011 and December 2015. The study included patients with infertility for
at least one year, full examination of monitoring ovulation, aged between 18 and
38 years, no more than 10 mm follicles on 1st examination monitoring, the sum of
the number of antral follicles between 6 and 24 between 2nd and 5th day of the
cycle, absence of oophorectomy, no more than 40mm fibroids and/or submucosal
and/or endometriosis tumors, FSH below 10UI/L, TSH between 0.5 and 4.5mU/L, and
serum prolactin < 20mcg/L. We did not included patients diagnosed with
polycystic ovary syndrome, smokers or those who reported drinking alcohol
frequently.
The patients were divided into two groups: those who reported having a regular
cycle and those who reported irregularity of cycles. The definition of a regular
cycle has been established in accordance with the International Federation of
Gynecology and Obstetrics - FIGO ( Table
1 ). The monitoring then identified those who ovulated and those who did
not ovulate in the cycle in question ( figure
1 ).
Figure 1 Study design
Study design
The presence of ovulation was found only in those cycles in which the follicle
reached at least 16mm in diameter. The ovulation day calculation was performed
according to the protocol suggested by Mikolajczyk et al . (2008) . If the follicle reached
18mm or greater diameter, the ovulation day is considered as the day immediately
following the largest follicle reaching a diameter before collapsing. In the
case of follicular diameter between 16 and 18 mm, the second day after the
examination before the collapse was considered as the day of ovulation. If the
interval between these exams were more than five days, the patient was excluded
from the study. A follicle collapse was considered upon the disappearance or
decrease of at least 70% of its diameter.
To compare the groups of those who reported that they had a regular cycle and
those who reported irregularity of cycles, they had to have similar
characteristics so as to not influence the evaluation of the study variables.
Both groups had to have a similar ovarian reserve, evaluated in this study by
age, FSH, and the antral follicle count by ultrasound between the 2 nd
and 5 th day of the cycle. Other factors can influence ovulation, such
as thyroid function and serum prolactin levels. For this reason, both TSH values
were matched as to the prolactinaemia between case and control groups. Although
the menarche age, the number of pregnancies, births (parity), abortion,
caesarean sections and Bilateral Tubal Ligation (BTL), do not have a direct
relationship with the ovarian reserve or the possibility of ovulation during the
ovulatory cycle, we consider it important to also pair these variables, to
ensure group comparability. Samples of the groups were thus paired according to
age, the age of first menstruation (menarche), the number of pregnancies,
births, abortions and cesarean sections, the number of antral follicles counted
between 2nd and 5th day of the cycle, BTL count, and the amount of laboratory
tests of FSH (IU/L), prolactin (mcg/L) and TSH (mU/L) ( Table 2 ). All inclusion criteria were based on the fact that
they are factors that influence the menstrual cycle and fertility of women, and
they may become confounders.
Results from the t-test for unrelated samples, Mann-Whitney and Fisher’s
exact test to assess the pairing of variables.
P =0.05
The paired data was submitted to the Shapiro-Wilk test, standard deviation
calculation and value of Z to evaluate the type of data distribution: normal or
not normal. The t test was used for normally distributed variables and the
Mann-Whitney's test for non-normal distribution and Fischer's test for binomial
variables. The test to evaluate the correlation between the cycle of regular
reporting and presence or absence of ovulation, was the Fischer's test. The
program used to perform the statistical tests was the SPSS 22.0.
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