# Can early pregancy be a contributing factor to cancer (womb or maybe otherwise) **URL:** \ **Category:** Factual Questions\ **Created:** [February 27, 2019, 8:14am UTC](https://boards.straightdope.com/t/can-early-pregancy-be-a-contributing-factor-to-cancer-womb-or-maybe-otherwise/830281 "2019-02-27T08:14:04Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![Barack\_Obama](https://avatars.discourse-cdn.com/v4/letter/b/dc4da7/32.png) [@Barack\_Obama](https://boards.straightdope.com/u/Barack_Obama)\ **Post date:** [February 27, 2019, 8:14am UTC](https://boards.straightdope.com/t/can-early-pregancy-be-a-contributing-factor-to-cancer-womb-or-maybe-otherwise/830281/1 "2019-02-27T08:14:04Z")
Are there any statistics or studies on this. To clarify the title I’m asking if an underage female is at increase likelihood of getting specific cancers (IE womb) from becoming pregnant at early ages. Are there any studies on this, statistics, etc… ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [February 27, 2019, 9:31am UTC](https://boards.straightdope.com/t/can-early-pregancy-be-a-contributing-factor-to-cancer-womb-or-maybe-otherwise/830281/2 "2019-02-27T09:31:06Z")
I think the only form of cancer that’s significantly correlated with pregnancy is hormone-receptor-positive breast cancer - which is most breast cancer. Early-age pregnancy\*\* reduces\*\* lifetime risk substantially, because pregnancy reduces estrogen and progesterone production. These hormones stimulate cell proliferation in receptor-positive malignant cells. > **[Reproductive History and Cancer Risk](https://www.cancer.gov/about-cancer/causes-prevention/risk/hormones/reproductive-history-fact-sheet)** > > A fact sheet that describes what is known about the relationship between pregnancy, miscarriage, abortion, fertility treatment and the risk of cancer. > [@](#): > > Women who have their first full-term pregnancy at an early age have a **decreased** risk of developing breast cancer later in life. For example, in women who have a first full-term pregnancy before age 20, the risk of developing breast cancer is about half that of women whose first full-term pregnancy occurs after the age of 30. It seems to be a complex picture, with relative risk rising and then falling. But since few young women get cancer, the reduction in risk later in life dominates. > **[NIH scientists find that breast cancer protection from pregnancy starts...](https://www.nih.gov/news-events/news-releases/nih-scientists-find-breast-cancer-protection-pregnancy-starts-decades-later)** > > Breast cancer risk remains elevated 20-30 years after childbirth. Other cancers, I don’t know. It appears (I’m just googling now) that 3 or more full-term pregnancies are a minor risk factor for cervical cancer, but I see nothing about age of first pregnancy. ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [February 27, 2019, 9:37am UTC](https://boards.straightdope.com/t/can-early-pregancy-be-a-contributing-factor-to-cancer-womb-or-maybe-otherwise/830281/3 "2019-02-27T09:37:28Z")
D’oh, that first article I linked has a section on other cancers. > **[Reproductive History and Cancer Risk](https://www.cancer.gov/about-cancer/causes-prevention/risk/hormones/reproductive-history-fact-sheet#q5)** > > A fact sheet that describes what is known about the relationship between pregnancy, miscarriage, abortion, fertility treatment and the risk of cancer. > [@](#): > > Women who have had a full-term pregnancy have **reduced** risks of ovarian and endometrial cancers. Furthermore, the risks of these cancers decline with each additional full-term pregnancy. > > Pregnancy also plays a role in an extremely rare type of tumor called a gestational trophoblastic tumor. In this type of tumor, which starts in the uterus, cancer cells grow in the tissues that are formed following conception. > > There is some evidence that pregnancy-related factors may affect the risk of other cancer types, but these relationships have not been as well studied as those for breast and gynecologic cancers. ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [February 27, 2019, 10:20am UTC](https://boards.straightdope.com/t/can-early-pregancy-be-a-contributing-factor-to-cancer-womb-or-maybe-otherwise/830281/4 "2019-02-27T10:20:28Z")
On the flip side - the earlier a woman starts menstruating the higher her risk of certain cancers. So, while pregnancy itself might not cause an increased risk (indeed, as already mentioned it might even lower it), a woman who start menstruating early enough to get pregnant at, say 13 or 14 might be at higher risk because of the earlier menstruation than a woman who didn’t start cycling until 16 or 17. Thus, a history of very early pregnancy might be correlated with an increased risk, but not caused by the pregnancy but rather something else. ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [February 27, 2019, 12:33pm UTC](https://boards.straightdope.com/t/can-early-pregancy-be-a-contributing-factor-to-cancer-womb-or-maybe-otherwise/830281/5 "2019-02-27T12:33:38Z")
I saw an article once (sorry, don’t remember where) discussing menstruation and cervical cancer (and other cancers of the female reproductive system). There was an ethnic group in Africa where the women must go to a different house when they are menstruating, and they had some sort of “attendance records”. Based on these statistics, the hypothesis was that in fact, due to factors like nutrition and regular pregnancies - modern western lifestyle women have significantly more periods than was normal in centuries and millennia past - they start earlier, finish later with fewer interruptions. The guess was women today have up to twice as many periods as the human body used to have, and this put much more stress on the reproductive system and was a contributing factor to modern cancer rates. So if anything, the OP’s question is backward according to this hypothesis. And then there’s Reimann’s point that hormones may contribute, which suggests birth control pills also are a possible factor. IIRC the reason hormone replacement therapy for women who have had hysterectomies is not as strongly recommended today is due to cancer risk. ---
**Author:** ![Yeah](https://avatars.discourse-cdn.com/v4/letter/y/dbc845/32.png) [@Yeah](https://boards.straightdope.com/u/Yeah)\ **Post date:** [February 27, 2019, 11:57pm UTC](https://boards.straightdope.com/t/can-early-pregancy-be-a-contributing-factor-to-cancer-womb-or-maybe-otherwise/830281/6 "2019-02-27T23:57:59Z")
Pregnancy at an early age is associated with early “sexual debut.” In general, early sexual debut is associated with increased numbers of sexual partners and hence an increased risk of HPV infection. Certain HPV infections cause cervical cancer. So a young girl who get pregnant might be at increased risk of cervical cancer, but not because she got pregnant. ---
**Author:** ![purplehorseshoe](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/purplehorseshoe/32/2996_2.png) [@purplehorseshoe](https://boards.straightdope.com/u/purplehorseshoe)\ **Post date:** [February 28, 2019, 9:42am UTC](https://boards.straightdope.com/t/can-early-pregancy-be-a-contributing-factor-to-cancer-womb-or-maybe-otherwise/830281/7 "2019-02-28T09:42:14Z")
The stats about women who’ve been pregnant having lower cancer risks makes me wonder if that’s a by-product of having an otherwise healthier uterus/cervix etc. (Correlation not equaling causation, and all that.) In other words, a less cancer-prone woman is more likely to get pregnant easily, or a woman more susceptible to cancer has lower fertility in general. ---
**Author:** ![jferigura](https://avatars.discourse-cdn.com/v4/letter/j/bc79bd/32.png) [@jferigura](https://boards.straightdope.com/u/jferigura)\ **Post date:** [February 28, 2019, 10:02am UTC](https://boards.straightdope.com/t/can-early-pregancy-be-a-contributing-factor-to-cancer-womb-or-maybe-otherwise/830281/8 "2019-02-28T10:02:23Z")
for me pregnant women don’t have an increased risk of developing cancer compared to women who are not pregnant. ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [February 28, 2019, 3:21pm UTC](https://boards.straightdope.com/t/can-early-pregancy-be-a-contributing-factor-to-cancer-womb-or-maybe-otherwise/830281/9 "2019-02-28T15:21:31Z")
> [@purplehorseshoe](#): > > The stats about women who’ve been pregnant having lower cancer risks makes me wonder if that’s a by-product of having an otherwise healthier uterus/cervix etc. (Correlation not equaling causation, and all that.) In other words, a less cancer-prone woman is more likely to get pregnant easily, or a woman more susceptible to cancer has lower fertility in general. No, that’s not the case. By far the strongest link is with hormone-receptor-positive breast cancer, which is about three-quarters of breast cancer. The basic causal relationship is well understood at the cellular and molecular level. The malignant cells have receptors for estrogen and/or progesterone, and these hormones stimulate cell proliferation. The protective effect from pregnancy (especially early pregnancy) is because pregnancy modulates the production of these hormones.