GYN CHRONICLES
Post-Term Pregnancy
By Dr. Maureen Owiti
I
was about to write about preterm
labor and prematurity but went
through my archives and found I have
previously discussed the topic. Reason
being I was recently invited by Harriet
Kinga and Prisca Aroko of Family Media
Radio & TV to discuss this in celebration
of World Prematurity Day (November
17th)! So I’ll take this opportunity to say
“THANK YOU” to the team, it was a
great show.
Meanwhile that leaves me without a topic
but hurrah why not discuss the opposite
i.e. post-term pregnancies.
For those of you who have ever been
pregnant, have you ever had the experience
when you’ve reached your due date and
nothing is happening … You call your
doctor and they are casual, telling you
there’s nothing to worry about?
Many women come to me and complain
doc I’ve passed or reached my due dates
and want an immediate induction and we
have great pains explaining to them that
there is nothing wrong with them or the
baby and they need more time and baby
will come when he or she is ready. The
reason for this is that we calculate their
due date based on the last menstrual
period and this is normally 40 weeks from
the first day of the last period.
A notable personality, who delivered this
way is the Duchess of Cambridge Kate
Middleton who delivered at 41 weeks to
Prince George 3rd in line to the British
crown.
38 MAL21/17 ISSUE
So what is a post-term
pregnancy? factors and anomalies such as anencephaly
(babies without parts of the brain and
skull).
A post-term pregnancy is one that has
done 42 completed weeks from first day
of last menstruation. The challenge comes
in that a good number of women don’t
know or can’t recall exactly when the last
menstruation was. The reason we put 42
completed weeks is that if a woman is 41
weeks and 1 day up to 6 days she is in the
42nd week of pregnancy but post-term
will be 42 completed weeks i.e. 42 weeks 0
days and greater. Why are we so concerned
about 42 weeks?
How often do post-term
births occur?
The incidence varies between 3-12%.
One study estimated that when last
menstrual period alone is utilized, 6.4%
are diagnosed to be post-term but if early
ultrasound alone was used, 1.9% meet the
cut, implying that menstrual dates are
frequently inaccurate in predicting post-
term pregnancy.
What are the causes and
risk factors for post-term
delivery?
The most frequent cause of a post-term
pregnancy diagnosis is inaccurate dating
as discussed earlier. Risk factors for
actual post-term pregnancy include first
pregnancy, prior post-term pregnancy,
male gender of the fetus, and genetic
The reason for this is that post-term
pregnancies face certain complications.
What is known is that the incidence of
perinatal mortality (death of baby) is
higher if a pregnancy is post-term. It can
occur prior to onset of labor (antepartum),
during labor (intrapartum) and after
delivery (neonatal).
Caeserean section rates for poor progress
of labor (dystocia), foetal distress is also
higher in post-term pregnancies. Rates
of admission to neonatal intensive care
units and neonatal seizures or convulsions
are also noted to be higher in these
pregnancies. Some fetuses also develop
post-maturity syndrome.
What is post-maturity syndrome? This is
when the baby has certain features after
delivery that include: wrinkled, patchy,
pealing skin especially on palms and soles;
a long thin body suggesting wasting; and
advanced maturity as baby is open-eyed,
very alert and appears old and worried
looking; with typically long nails.
Management
If a woman is diagnosed to be 42 weeks,
what typically happens is efforts to ensure
that the dating is accurate and tests on the