induction of labour – post dates pregnancy - National Women's ...

Auckland District NATIONAL WOMEN’S – MATERNITY Clinical Practice
Health Board (Section 3) Manual
Policy Statements
INDUCTION OF LABOUR
– POST DATES PREGNANCY
Policy Statements Gestation should be calculated from the woman’s last menstrual
period. If ultrasound dating differs from the menstrual dating then
the margin of error of the scan should be considered. If the
discrepancy between the menstrual dating and scan dating is more
than the margin of error for the scan and the menstrual dating is sure,
then the menstrual dating should be confirmed as correct.
The margin of error of the scan is calculated by taking 8% of the
gestation in days.
Examples of margin of error :
6 wk +/- 3 days
7 wk +/- 4 days
8 wk +/- 4.5 days
10 wk +/- 5.5 days
16 wk +/- 9 days
20 wk +/- 11 days
Management of pregnancies continuing beyond 41 weeks requires
consultation with a specialist either at ANC at Greenlane Clinical
Centre or a private obstetrician consultation.
Routine antenatal care (i.e. Weekly visits) is not a safe option after
41 weeks gestation.
Discussion with the woman regarding her options for ongoing care
must occur at around 41 weeks (EDD 40 weeks plus 5 days to EDD
40 weeks plus 9 days).
Induction of Labour should be arranged promptly in the following
circumstances:
Maternal hypertensive disease
Maternal diabetes
A small-for-gestational-age baby
Any other concern regarding maternal or fetal condition
If reduced movements or reduced liquor are present.
Section: National Women’s – Maternity Issued by: Clinical Director O&G
File: Induction Labour Post Dates Apr12.doc Authorised by: Clinical Director O&G
Classification: NMP200/SSM/063 Date Issued: Reviewed April 2012
Induction of Labour – Post Dates Pregnancy Page: 5 of 9
Continued on next page