Notice: You are viewing an unstyled version of this page. Are you using a very old browser? If so, please consider upgrading

Breast Cancer in Pregnancy

Key points

  • The diagnosis of breast cancer in pregnancy can have devastating consequences for women and their families.
  • Treatment regimens vary and we do not know either the incidence of newly diagnosed breast cancer or the short-term outcomes for women and their babies.
  • Little is known about what choices women make when continuing with pregnancy.
  • The knowledge gained from this study will enable further study of all breast cancer in pregnancy and longer term outcomes in the UK.

Surveillance Period

1st October 2015 – 30th September 2017


The actual incidence of breast cancer in pregnancy in the UK is not known. Estimates from other countries range from 2.4 to 7.8 cases per 100,000 births. This gives an estimated 18 to 61 cases per year in the UK. We are seeing women with a history of breast cancer now getting pregnant as survival rates increase, but surveillance of this would inform a further study in the future. Although the incidence of breast cancer rises with age, the observation that many women are delaying their families until later in life means that the incidence of breast cancer arising for the first time in pregnancy may be rising. At the other end of the scale, for women under 30, a significant proportion (more than 10%) of breast cancers may be associated with pregnancy, or within a year afterwards.

The diagnosis of breast cancer in pregnant women may be difficult[1] and there is a potential for under-treatment of the mother and iatrogenic prematurity for the fetus. Due to its relative rarity, we lack a standardised approach to managing these women. There is also an apparent contradiction between advice in Europe in general[2] and UK specific advice from the RCOG about the timing of interventions and delivery[3]. A group in Australia and New Zealand are conducting a similar study, which will make comparisons hugely informative[4].

It is clear that such cases should be managed within a multidisciplinary team within established cancer networks, in close liaison with obstetric and paediatric teams. Treatment is influenced by a number of factors, including histological grade, receptor and HER2 (Human epidermal growth factor receptor 2) status and suspicion of metastases. There is variation in approach to surgery and chemotherapy regimens that have yet to be described. A 2-3 week gap is recommended after last chemotherapy prior to delivery in order to reduce the problems of neonatal neutropenia, for example, but this may not always be possible or planned.


To use the UK Obstetric Surveillance System (UKOSS) to determine the incidence of primary breast cancer in pregnancy in the UK and to describe its management as well as the short-term outcomes for both mother and infant.

Research questions

  • What is the current incidence of primary breast cancer in pregnancy in the UK?
  • How does breast cancer present and at what gestation?
  • How is breast cancer managed in pregnancy in the UK?
  • Is there variation in the timing of surgical intervention?
  • What are the short-term outcomes for mother and infant?

Case definition

Any woman meeting one of the following criteria:

  • Newly diagnosed case of breast cancer during pregnancy.
  • First pathological diagnosis of breast cancer during pregnancy.
  • A new confirmed diagnosis of breast cancer during pregnancy determined from the medical records.


  • Breast cancer diagnosed before pregnancy.
  • Recurrence of breast cancer in current pregnancy.


This study is being funded by the Betsi Cadwaladr University Health Board (BCUHB).

Ethics committee approval

This study has been approved by the North London REC1 (REC Ref. Number: 10/H0717/20).

Lead Investigator

Philip Banfield, Claudia Hardy, BCUHB North Wales; Julie Jones, North Wales Cancer Centre; Sarah Davies, Lynda Sackett, BCU Health Board North Wales; Marian Knight, NPEU

Data Collection Form

UKOSS Breast Cancer in Pregnancy Form


  1. ^ Ayyappan AP, Kulkarni S, Crystal P. Pregnancy-associated breast cancer: spectrum of imaging appearances. The British journal of radiology. 2010;83(990):529-34.
  2. ^ Amant F, Deckers S, Van Calsteren K, Loibl S, Halaska M, Brepoels L, et al. Breast cancer in pregnancy: recommendations of an international consensus meeting. European journal of cancer. 2010;46(18):3158-68.
  3. ^ RCOG. Green-top Guideline no. 12. Pregnancy and Breast Cancer 2011. Available from:
  4. ^ AMOSS. Available from: Breast Cancer (GBC) June2013_1371468215.pdf.

Updated: Tuesday, 17 January 2023 18:01 (v16)