When everything feels louder during pregnancy

Autistic Mirror (Inside view)

Pregnancy fundamentally changes the hormonal baseline, and that baseline directly carries the sensory filter system.

Sensory gating is a preconscious filter system: before a stimulus becomes conscious, the brain screens out a large part of it. In autistic people this sieve is more permeable from the start than in the neurotypical comparison, which means more raw material arrives at the cortical level. In pregnancy, oestrogen and progesterone shift massively and directly influence the strength of this pre-filtering inhibition. Concretely: oestrogen modulates GABA receptors, which are responsible for inhibitory signalling in the filtering process. If this inhibition becomes weaker through hormonal restructuring, even more raw material is let through, and that on a baseline that already filters less. The result is not a new sensitivity, but a further opening of a channel that was already wider open than in neurotypical people.

Smells are a special case neuroanatomically: the olfactory system has the most direct access to processing, with fewer intermediate stages than hearing or touch. Pregnancy hormones additionally change blood flow in the mucous membranes and receptor density in the nose, which increases sensitivity to certain compounds. In a filter system that already dampens little in advance, this double change means that smells not only act more strongly but are also harder to ignore.

Touch sensitivity follows a similar path: skin receptors become more sensitive in pregnancy because the immune system and the peripheral nervous system change. This effect is also detectable in non-autistic pregnant people, but in autistic people it meets a central processing mechanism that dampens tactile signals less and weights them more strongly.

So what you describe is the overlap of two levels: a hormonally driven change in filter performance that meets an already differently calibrated sensory processing. The stimuli are not actually louder or closer, they pass through more layers to conscious perception, and with less dampening than before.

Autistic Mirror (Inside view)

Two processes run on top of each other here, and they reinforce each other.

Autistic burnout was already part of the picture before the pregnancy. That means: the sensory and cognitive budget is chronically reduced, because masking and accumulated stimulus load have used up capacity over a long time that has not fully recovered. Abilities that used to run as a matter of course now cost more than before.

Pregnancy places a considerable physical load on this already reduced budget. In pregnancy the brain massively prioritises metabolic resources for foetal development. At the same time, progesterone and other hormones change to an extent that directly influences neural processing: preattentive filtering, meaning the automatic filtering out of background stimuli, works measurably differently under hormonal load. What used to stay in the background now comes through more strongly. Sensory gating refers to exactly this early, automatic filter layer that determines which stimuli never reach awareness at all. If this gating is less stable, every stimulus costs more processing, even if it is objectively as loud, bright or complex as ever.

The result: a day that used to count as "normal" and was still somehow manageable now exceeds the available budget. The brain responds to falling below budget with withdrawal. This is not a collapse and not a weakness, but the same prioritisation logic as in any shutdown. Less input, less processing, redirect energy to what is essential.

So withdrawal here is a regulation mechanism, not a symptom directed against you. It signals that the daily workload that still fitted before the pregnancy is now systematically set too high.

Autistic Mirror (Inside view)

Pregnancy drastically multiplies the amount of signals the body sends. For a nervous system that already processes interoceptive signals at a lower resolution, this means: more noise on a channel that was not reliable before.

Interoception describes how the brain processes body signals. The anterior insula collects input from the whole body, such as hunger, thirst, pain, tension and warmth, and passes it on to conscious perception. In many autistic people this signal arrives at a lower resolution, delayed or in bursts rather than continuously. What the insula reports does not automatically land in awareness as a clear sensation.

In pregnancy several things now come on top at the same time.

The body continuously produces new signals for which there is no frame of reference: a feeling of pressure in the lower abdomen, changed bladder capacity, the child's movements, hormonally driven exhaustion that feels different from normal tiredness. The brain has to classify these signals but has no stored pattern for them. If interoceptive resolution is already weak, an unfamiliar signal often simply stays unassigned, readable neither as "hunger" nor as "nausea", but as diffuse discomfort.

At the same time, hormonal foundations shift. Progesterone and oestrogen modulate, among other things, how the nervous system weights signals. This additionally affects the already different interoceptive processing pathways and can lead to thresholds shifting, meaning that things that could eventually be noticed before now appear even later or in a different form.

Alexithymia is often a second mechanism involved here. It does not concern the body signal itself, but the step after it: assigning the signal to a word for a feeling or sensation. So when a signal arrives, the question "What is this?" often cannot be answered directly. In pregnancy, new signals meet a naming process that was laborious for familiar states and is at first not available at all for unfamiliar ones.

In addition, nausea in pregnancy is mediated anatomically differently from ordinary nausea. The brain responds to hormonal signals and changed gastrointestinal motility, and this GI signal runs via afferent vagal pathways. Autistic people more often have differences in gastrointestinal processing, so this pathway is already calibrated differently at baseline. That means: the signal can be stronger than perceived, or arrive more diffusely distributed, which further complicates classifying it as "nausea" rather than "general unwellness".

The result is not inattention but a genuine gap in perception. The body sends, but the signal does not arrive in the form that external structures assume, namely as clear, time-locatable hunger or pain.