What happens in your body during a miscarriage? - Nassim Assefi and Emily M. Godfrey
Globally, around 23 million pregnancies
end in miscarriage each year.
Despite how common it is, miscarriage
is still considered a taboo subject.
The experience can feel isolating,
and for some, emotionally traumatizing.
And myths about miscarriage
add to the stigma,
leading many to blame themselves
for the loss.
However, most miscarriages
are unpreventable
and caused by factors
beyond a person’s control.
They happen because pregnancy
is a complex process,
which requires careful choreography
between the fertilized egg and uterus.
In fact, of every three eggs
that are fertilized,
only one progresses to a live birth.
So, let’s take a closer look at what
happens in the body
during the first 12 weeks of pregnancy,
when a majority of miscarriages occur.
Pregnancy is maintained
by several hormones:
progesterone and estrogen,
produced within the ovaries,
and human chorionic gonadotropin, or hCG,
sent out by the fertilized egg.
During the first half of each
menstrual cycle estrogen levels increase,
followed by an increase in progesterone.
These hormones signal to the uterine
lining to enhance its blood supply
and thicken its mucosa,
creating the conditions needed
for an early pregnancy to grow.
If an egg arrives at the
uterus unfertilized,
these hormone levels naturally drop,
triggering contractions and the shedding
of the uterine lining in menstruation.
Yet, if the egg arrives fertilized,
its outermost layer begins producing hCG.
This hormone travels to the ovaries
and stimulates the continued release
of progesterone and estrogen,
halting menstruation.
hCG also binds to receptors
on the uterine lining
to prevent it from rejecting
the fertilized cell mass as it embeds.
This is a stage where things
often go awry.
For reasons that are not fully understood,
as many as one third of fertilized eggs
fail to properly attach,
passing undetected in a normal-seeming
menstrual period.
And implantation is only the first hurdle
for fertilized eggs
that do properly attach.
Once burrowed in the uterine lining,
the rapidly dividing fertilized egg’s
own DNA guides its growth.
Chromosomal abnormalities can therefore
cause irregular development,
or stop embryo growth entirely.
While many mistakenly believe their
miscarriage was caused by factors
like stress, exercise, vaccination,
or past birth control use,
a vast majority are in fact caused
by these genetic issues
or other health factors
beyond a person’s control.
Some pregnancy losses lead to few, if any,
noticeable physical symptoms.
In other cases, hCG levels drop,
followed by a decrease in progesterone,
causing bleeding and cramping.
In either situation,
there are three treatment options—
two of which are also used
for induced abortion procedures,
when patients choose to end a pregnancy.
The first of the three options is
what’s commonly known
as the “watch-and-wait” method.
A person waits for pregnancy hormones
to drop further,
allowing the pregnancy tissue to be
released with the shedding uterine wall.
This approach works up to 90% of the time,
but it can involve several weeks
of unpredictable pain and bleeding.
Others may opt for option two,
taking the pills mifepristone
and misoprostol in sequence.
The first works hormonally,
by blocking progesterone receptors,
and the second mimics a molecule
which induces labor,
stimulating uterine contractions and
causing the cervix to soften and dilate.
After taking the second pill,
the process normally takes 1 to 6 hours.
It’s often safely self-managed,
and can be done privately at home.
The third possible treatment option
is known as vacuum aspiration.
During this five-minute procedure,
the healthcare provider numbs the cervix,
then places a thin tube connected
to a syringe-like device
to remove the pregnancy tissue.
Treatment choice is often based
on the pregnant person’s medical history,
timeline, expectations,
and personal preferences,
and all three methods have proven
to be safe and effective.
However, without the medication
or vacuum aspiration options,
an untreated or an incomplete miscarriage
can lead to life-threatening infections
and hemorrhage.
And because they are the same treatments
used in induced abortion care,
they can be harder to access
and even criminalized in some areas.
Beyond this, over half the world’s
population lacks access
to reliable basic healthcare,
including these essential
reproductive health services.
While pregnancy means different
things to different people
at different points in their lives,
for many, losing a pregnancy can be
devastating and overwhelming.
During this difficult time,
everyone deserves to be met
with care and support,
and to have access to these
life-saving treatments.
