Trimester 1
Usually down
Nausea, fatigue, progesterone. Desire often roughly halves versus baseline.
Pregnancy
Trimester moves desire. Fetal sex does not.
Across 59 studies (von Sydow 1999), sexual interest typically falls in the first trimester, returns or rises in the second, and falls again in the third. The boy-versus-girl split that folklore promises does not show up in maternal blood testosterone, and has never been established for libido.
Trimester 2
The rebound
Energy and genital blood flow rise. This is the only stretch that commonly matches or exceeds pre-pregnancy hunger.
Trimester 3
Usually down again
Discomfort, size, reflux, sleep. Most couples still have some sexual contact; frequency drops.
Orgasm
Often more intense. Not a new pathway. Still the clitoris.
Easier or stronger — for many, in the second trimester
ModeratePelvic blood flow rises in pregnancy. The clitoris, vulva, and vaginal wall sit more engorged, which is the same physiology that makes orgasm feel bigger. Healthline's clinical summary and obstetric writing converge: many women report more pleasurable, sometimes quicker orgasms once nausea lifts. First-trimester nausea and third-trimester bulk work the other way. This is a trimester effect, not a fetal-sex effect.
Clitoral. Pregnancy does not unlock penetrative orgasm.
High confidenceIn non-pregnant samples, only about 18% of women orgasm from penetration alone; most partnered orgasms need clitoral stimulation (NSSHB event-level work; Wallen & Lloyd). Nothing in the pregnancy literature shows that ratio flipping. Extra vascularity can make penetration feel better. It does not rewire the organ that actually fires the orgasm for the large majority. In the third trimester, deep penetration is often less comfortable, so clitoral, oral, and manual routes become even more of the repertoire.
How the orgasm was reached, as a share of orgasms — not a share of women. Pregnancy column is second-trimester weighted. Penetration-alone does not jump.
- Orgasm can trigger uterine contractions that feel like mild Braxton-Hicks. In an uncomplicated pregnancy this is considered safe.
- Sustained engorgement makes a second orgasm slightly more available for some women — the same mechanism as late-arousal non-pregnant sex, turned up.
- Anxiety about harming the fetus is a more common orgasm-killer than any hormonal deficit. Reassurance (from a clinician, in a low-risk pregnancy) moves this number more than a toy does.
Pregnancy changes the body and the logistics. It does not install a new fetish, and fetal sex does not either.
More partner, less stranger
When desire returns in the second trimester it is usually aimed at the known partner. Novel-partner and public-risk scenes recede. The narrative gets closer, not stranger.
Breasts and being desired as pregnant
Breast sensitivity is real (estrogen, blood flow). Some women eroticize the pregnant body — fullness, being wanted 'like this.' Others find the same changes aversive. Both are common. Neither is a boy-vs-girl effect.
Power fantasies often soften into being cared for
The 'overpowered' script, when it stays, is more often tender-dominant than violent. Clinical write-ups describe this; there is no large coding study. Treat as low-confidence.
Less visual porn, more audio and imagery
Nausea, shared beds, and not wanting to look at gymnastic bodies push the mix toward mental imagery and headphones. Audio erotica's pitch (no screen, eyes closed) fits pregnancy unusually well.
What does not change
Carrying a boy does not add a testosterone-flavored kink. Carrying a girl does not add an estrogen-flavored one. Maternal serum T does not differ by fetal sex. 'Breeding' as a porn tag is mostly used by people who are not pregnant.
Trimester curve
Boy and girl traces sit on top of each other on purpose. The dashed line is the hypothesized first-trimester nausea dip for female fetuses — well inside noise.
Want sex: not pregnant vs boy vs girl
Pregnancy-average (mean of three trimesters) against the non-pregnant age baseline. Fetal-sex columns are nearly identical by construction. Insufficient
Hormones, folklore, evidence
| Claim | What is actually known | Libido implication |
|---|---|---|
| Boys raise the mother's testosterone, so she is hornier | Maternal serum testosterone rises slowly in all pregnancies and does not differ by fetal sex. Amniotic (fetal) T is higher with male fetuses — that is the baby's hormone. Sim 2020: higher maternal T is associated with lower partnered desire. | None demonstrated. Opposite of the folk model if anything. |
| Girls raise the mother's estrogen, so mood/desire change | Maternal estrogen rises in every pregnancy. Most studies find no fetal-sex difference in maternal blood. One Scandinavian sample reported ~9% higher early estrogen with girls. | Unproven. 9% is not a libido study. |
| Girls cause worse morning sickness, so less sex | hCG is slightly higher with female fetuses. Severe nausea (hyperemesis) is modestly more common with girls in some cohorts. | Plausible tiny first-trimester effect via nausea, not via a 'girl hormone.' Flagged insufficient. |
Four pregnancy cells
These exist because the question asked for them. Every estimate in this block is a trimester-averaged scenario model on top of the age baseline — not a survey of women who knew fetal sex. Confidence is insufficient on every fetal-sex cell.
Thoughts
Think about sex
7.3/day
Range 2.2–13.1 · Boy · 18–30
Fetal sex does not change maternal circulating testosterone (The Conversation 2017 review). These numbers are the pregnancy average, not a boy-specific libido boost. Trimester pattern (von Sydow 1999): desire falls in T1, rebounds in T2, falls in T3. Baseline: Fisher 2011 college women averaged ~10 sexual thoughts/day on a tally counter (men ~19). Individual range is enormous; erotophilia predicts counts better than age. Social-desirability bias systematically suppresses women's reports.
Desire
Want sex
2.9/week
Range 0.7–6.9 · Boy · 18–30
Fetal sex does not change maternal circulating testosterone (The Conversation 2017 review). These numbers are the pregnancy average, not a boy-specific libido boost. Trimester pattern (von Sydow 1999): desire falls in T1, rebounds in T2, falls in T3. Baseline: A synthesis of Natsal frequency, NSSHB partnered-sex prevalence (highest at 20–29), and desire-discrepancy studies. Many women this age describe responsive rather than spontaneous desire, so 'want' undercounts arousal that appears after initiation.
Fantasies
Fantasize about sex
1.3/day
Range 0.2–3.9 · Boy · 18–30
Fetal sex does not change maternal circulating testosterone (The Conversation 2017 review). These numbers are the pregnancy average, not a boy-specific libido boost. Trimester pattern (von Sydow 1999): desire falls in T1, rebounds in T2, falls in T3. Baseline: Elaborated scenes, not fleeting thoughts. Leitenberg & Henning: 90–97% of women report fantasies. Easton 2010 found 18–26-year-olds fantasize less often and less intensely than 27–45.
Enjoyment
Enjoy sex
62% of events
Range 52–72 · Boy · 18–30
pleasurable last event: 62%
Fetal sex does not change maternal circulating testosterone (The Conversation 2017 review). These numbers are the pregnancy average, not a boy-specific libido boost. Trimester pattern (von Sydow 1999): desire falls in T1, rebounds in T2, falls in T3. Baseline: Most partnered events are rated pleasurable in NSSHB event-level data. Enjoyment is high even when orgasm does not occur — pleasure ≠ climax.
Orgasm
Orgasm during sex
59% of events
Range 43–71 · Boy · 18–30
always orgasm: 28%
Fetal sex does not change maternal circulating testosterone (The Conversation 2017 review). These numbers are the pregnancy average, not a boy-specific libido boost. Trimester pattern (von Sydow 1999): desire falls in T1, rebounds in T2, falls in T3. Baseline: NSSHB: 64% of women orgasmed at the most recent sexual event. Frederick 2018: heterosexual women orgasm ~65% of the time; lesbian women ~86%. YouGov UK: only 30% 'always.' Repertoire (clitoral stimulation, oral sex, duration) moves this number more than age.
Masturbation
Masturbate
2.7/month
Range 0–9.7 · Boy · 18–30
any in past month: 38.7%
Fetal sex does not change maternal circulating testosterone (The Conversation 2017 review). These numbers are the pregnancy average, not a boy-specific libido boost. Trimester pattern (von Sydow 1999): desire falls in T1, rebounds in T2, falls in T3. Baseline: NSSHB past-month prevalence: 26% (18–19), 44% (20–24), 52% (25–29). Population mean is pulled down by women who did not masturbate that month. Among those who did, a few times a month is the mode; weekly is common in the mid-20s.
Birth ends the second-trimester rebound. The year after is a trough — see postpartum.